![[image]](usbsync.png)
This page is a copy of the overview in the app's Help tab, styled for better reading in this web page. If you've already read the overview in Help, you may want to skip ahead to the GUI Guide for finer-grained usage details. If you're looking for app start-up info, try App Packages. For general coverage of this app's usage, read on here.
This page's sections present the essentials needed to use this app well. They explore:
Related: see also the app videos that demo concepts covered here.
Welcome to PC-Phone USB Sync — cloud-free backup and sync.
This app makes content folders the same on your PCs, phones, and removable drives. Compared to other tools, it's:
This app brings PC-level tools to all your devices. The content it manages isn't just contacts, calendars, and a few stray photos. It's an entire folder of your choice, including all its subfolders, photos, documents, music, and other media you value.
By using this app with a removable drive, you can both back up this content on your phone or PC to save it, and sync it between your devices to make it match: from PC to phone, from phone to PC, and any other way you find useful. Among its roles, this lets you:
In tech terms, this app's syncs are on-demand and one-way at a time; this keeps you in control, and avoids lossy conflicts. They can also be run in any direction and modify just the items you've changed; this makes them flexible, and faster and gentler on your drives than simple copies.
Perhaps best of all, this app uses your USB ports and removable drives for its backups and syncs, to avoid both slow networks and the privacy perils of clouds. With this app, your stuff remains your stuff, not someone else's point of control.
To use this app, get it's Android version at the Play store, and fetch its PC versions for Windows, macOS, and Linux at quixotely.com. For most roles, you'll also need a removable drive to store and transfer content. An SSD or thumb drive attached by USB is common, but microSD cards, cameras, and other devices work in the app too.
This section provides a quick review of this app's usage model. Later sections go into more detail on specific usage modes, but the basics introduced here are straightforward. Covered here:
Before we jump into syncs, let's cover a few preliminaries. First off is terminology. In this app and this doc:
Next up, to use this app, you'll need to set up a drive and one or more versions of the app itself. Specifically, this app's usage requirements vary per your goals:
For example, to sync your PC to or from a phone, get the Android app, the version of this app for your PC, and a USB drive. To back up content only, get the app for your device plus a USB drive. There's more info about PC apps ahead.
For best results, removable drives used with this app should be formatted with the portable exFAT filesystem. All PCs and most phones support exFAT today, and most USB drives come preformatted with it. FAT32 works, but its timestamp limitations can trigger spurious syncs when your devices' time changes (more info), and other formats are not as portable. See the web for formatting tips.
Naturally, all the devices you'll be syncing to—USB drives, phones, and PCs—must have enough free storage space to hold a copy of your content folder (or folders, if you'll sync more than one). Most phones come with space to spare today, but bigger is better for content storage.
With those preliminaries in hand, we're ready to explore content syncs. Let's start with the general model first; it's simpler than the full details may suggest.
When using this app, you'll first collect your content files in a folder (or folders) using your local file explorer or other tool, and copy it to your devices with this app's COPY. Use subfolders to organize your content as desired; everything in your folder will be synced in full.
After the initial copy, you'll make changes on one device at a time, and push them to other devices with this app whenever you wish. These change propagations (a.k.a. syncs) use your USB ports and removable drive, and vary by usage mode:
In all modes, this app supports automatic rollbacks (i.e., undos) for all the changes its syncs make on each device. This helps ensure the safety of your content. You can even undo multiple syncs to reset your content to a prior state in the past.
Beyond copies and syncs, this app also has tools for verifying the content copies you'll create, along with portability utilities, configuration options, and help resources. We'll explore these later.
Finally, you'll implement the preceding section's model by running actions in the app, but this is similarly simple. All of the app's primary actions live on its Main tab; to run any one of them:
You can often skip right to step 3, because the app remembers your prior choices. Each action opens a popup to explain what it will do, remind you of your folder picks, and confirm its run. Main-tab actions all launch operations in the open-source Mergeall system, which is included with the app, and can be explored here and here.
To monitor an action's progress and results, inspect its logfile in the Logs tab: pick a file there, and click a green action button to view. TAIL shows the selected file's end, WATCH samples the logfile of the running action every second, and OPEN and EXPLORE open the selected file and the logfiles folder in your local viewers.
For ease, the Logs tab automatically selects and scrolls to the most-recent logfile at the top of its date-sorted list when opened. You can also use double and triple taps on logfile names in Logs to quickly run TAIL and TAIL+OPEN, respectively, and the popup shown on action exit includes brief logfile summary information that's often enough.
Logfile reports are straightforward, and include indicator lines at the end if there are any messages that warrant investigation (popup summaries show indicators too). If you see an indicator line, search logfiles for "*" to locate errors and notes, and see Tech Notes in this app's User Guide for more about logfiles in general.
Although it supports a variety of actions, this app's main tool is the SYNC button on its Main tab. This makes a TO folder the same as a FROM folder quickly, by updating TO only for changes made in FROM. SYNCs detect changes by checking timestamps, sizes, and folder structure, to avoid slower full copies. They can also be rolled back with UNDO if needed.
The way you'll use SYNC depends on whether you want to back up your content, sync it between PCs and phones, or both. The next two sections provide step-by-step coverage of both usage modes.
To use this app to back up content folders on your PC or phone, you'll need a removable USB drive to host the backup copy, and versions of this app for each device you'll be backing up. Get the Android version for your phones, and one of the versions of this app for your Windows, macOS, or Linux PCs.
See the tips above for more on the USB drive, and open this site's App Packages guide to fetch both Android and PC versions of this app. For backups, you'll copy content first, sync it later after changes, and verify it as desired, as the following sections will explain:
To get started, run an initial content-folder copy from your PC or phone to your USB drive, by selecting folders and using the app's COPY button once:
In step 2, you're choosing a folder on your USB drive to host the content copy: FROM's content folder is added to TO as a new subfolder. This first copy may be slow because it must copy your content in full, but later backups will be fast.
Thereafter, whenever you want to update your backup copy, run SYNC just once, with the PC's or phone's content copy as FROM, and the USB drive's copy as TO:
In step 2, you're choosing existing content-copy folders. Every time you run all three steps, your backup drive's content copy will be made the same as your device's copy.
These updates will be fast, because they change your USB drive's copy only for changes you've made on your PC or phone. Moreover, because the app remembers your FROM and TO settings between runs, you'll normally need to just attach your drive and press SYNC.
Keep in mind that the app's SYNC button is used for both content backups and device syncs. Here, it makes a backup copy the same as a live copy quickly, and works as an backup tool. Device syncs ahead will use it as a more general change-propagation tool.
To verify that your backup copy matches your device, attach your USB drive to your device and select as above, then run either SHOW or DIFF in the app. SHOW runs a fast timestamp-based comparison of FROM and TO; DIFF runs a complete byte-for-byte comparison, but is much slower because of this, and should be used only occasionally.
To restore your content from a backup, simply select the USB drive's content copy as FROM and your device as TO, and either SYNC to an existing copy, or COPY the USB drive's copy in full. Once restored, you can SYNC to your USB drive again to back up when desired.
Note that the UNDO button can roll back changes made to your USB drive's copy by a SYNC, but is rarely useful in backups mode. Also note that if you opt to sync PC and phone devices, your USB drive will automatically serve as a backup copy of your content, and no extra backup steps are required. To see how, we have to move on to the next section.
To use this app to sync content folders between PCs and phones, you'll need a removable USB drive to serve as a go-between for syncs, and versions of this app for each device you'll be syncing. Get the Android version for your phones, and one of the versions of this app for your Windows, macOS, or Linux PCs. See the USB-drive tips above, and open this site's App Packages guide to fetch Android and PC versions of this app.
Device syncs always update a destination device to match a source device, but can run in any direction. For instance, they can be run from PC to phone, from phone to PC, or between any combination of PCs and phones, and you need PC versions of this app only if there are PCs in the mix. Here, we'll focus on typical PC/phone syncs.
Device syncs also use an intermediate USB drive to propagate content and changes between your devices. This just means you'll run the app twice: once on the source to push to the USB drive, and then again on the destination to pull from the USB drive. In effect, your drive plays the same role as a remote server in cloud storage, but faster and safer.
By syncing to and from a go-between USB drive this way, your content copies on your PC and phone are made the same without being directly connected, and without compromising privacy. As a bonus, your USB drive becomes an extra backup copy of your content.
The following sections detail the steps you'll run to copy your content initially, sync it for changes later, and verify your content copies as desired:
Let's assume for now that your content lives on your PC initially. To get started, perform an initial content-folder copy from your PC to your phone, using your USB drive as a go-between, and running the Main tab's COPY on each device:
In both selection steps, you're choosing a folder on the destination to host the content copy: FROM's content folder is added to TO as a new subfolder. If your content instead lives on your phone initially, do the same as above, but swap PC and phone roles: copy phone to USB, then USB to PC.
Either way, the net result makes your content folder the same on your PC, phone, and USB drive. This first copy may be slow because it has to perform a full byte-for-byte copy, but later syncs will be much faster because they'll update TO only for changes in FROM.
After the initial copy, whenever you want to update your devices' content copies to be the same, simply run SYNC twice: once on the source device to sync to the USB drive, and then again on the destination device to sync from the USB drive.
For example, to sync your phone's content copy to reflect changes made in your PC's content copy, simply run SYNC on each device with the USB drive in between:
In both selection steps, you're choosing existing content-copy folders. Every time you run this procedure, it updates your phone for changes made on your PC, and makes your content copies the same again on your PC, USB drive, and phone.
Just as in backups, because this app automatically remembers the FROM and TO paths you used for prior runs on each device, the selection steps above aren't required for later runs if you sync the same way each time: on both PC and phone, simply attach your USB drive and press SYNC.
Likewise, to sync your PC's content copy to reflect changes made in your phone's content copy, simply run SYNC on each device with the USB drive in the middle:
Just like PC-to-phone syncs, you're choosing existing content-copy folders in both selection steps, and your content copies on your phone, USB drive, and PC are made the same again every time you run this. And here too, the selection steps above can often be skipped, because FROM and TO paths are saved on both your phone and your PC: just attach USB drive and SYNC on both devices to repeat prior syncs.
Besides syncing between a phone and a PC per the last two sections, this app can also be used to sync between two or more phones, two or more PCs, or a mix of many phones and PCs. These modes work like those already detailed: simply SYNC from the source device with changes to your USB drive, and then SYNC from your USB drive to one or more destination devices.
Because this app works the same on phones and all PCs, it supports arbitrary device combinations. This app can even be used to sync to or from a camera attached directly to a phone or PC, though cameras are generally better used as content sources, not destinations.
To verify that your device copies are the same, first verify your USB drive's copy to one device, then verify it to the other. If the USB drive's copy matches both devices, then the device copies are the same too (abstractly speaking: if A = B and B = C then A = C).
More concretely, to verify that your content copies match, attach your USB drive to your device, select one copy as FROM and the other as TO (the direction doesn't matter here), and run either SHOW or DIFF in the app. SHOW runs a fast timestamp-based comparison of FROM and TO; DIFF runs a complete byte-for-byte comparison, but is much slower because of it, and should be used only occasionally.
Also note that because your USB drive will always store an extra backup copy of your content, you can use it at any time to restore your PC, phone, or both: just run the app with your USB drive as FROM and your device as TO, and either SYNC (if the device's copy is usable) or COPY (to copy the content folder to the device in full and anew).
Finally, the app's UNDO button allows you to roll back all the changes made to any TO by the most recent SYNC run against it. This is a last-resort safety mechanism which you can use when syncs go awry, and fully restores TO to its pre-SYNC state. Though more rarely needed, you can also undo multiple SYNCs one at a time with multiple UNDOs: each one resets the TO folder to its state further in the past.
Important: UNDO works only if backups are enabled in the Config tab, which makes SYNC save changed items in TO's __bkp__ folder. This is enabled by default, and should generally be left this way; disabling SYNC backups can save some space and runtime, but means that SYNC changes are permanent. Mod with care.
To use this app, organize the content files you wish to back up or sync into folders as noted earlier. You can create and sync multiple content folders, but it's usually easier and quicker to use just one for all your content, or at least one for content that's prone to change. Use subfolders in your main folder to organize content by types, and sync either the main folder or individual subfolders.
You'll also need to choose a location to host your content folder on each device. The Main tab's folder choosers, opened by its blue buttons, allow you to pick folders in on-PC, on-phone, and removable-drive storage. Storage types are called out by label or other ID in the red radio buttons at the top of the chooser popup: scroll to see all of your storage types, and tap to go to a type's root folder at any time.
Once you've selected a storage type, you'll navigate among its folders much like you would in a file explorer: double-tap to open a folder, single-tap to select, use ../ or ..\ to go up one level, and toggle between icon and list views with the chooser's gray buttons. Your icon-or-list view preference can also be made permanent in the Config tab.
You can store your content nearly anywhere in any storage type, but it must be accessible to this app, as well as file explorers and programs you'll use for content views and changes. The following sections provide tips on storage options per device type:
C: on Windows, and / on macOS and Linux. It gives access to everything on the drive, including your home (PC) folder, though some parts of ROOT may not be usable due to permission rules; see your platform for details.
On Unix PCs (macOS and Linux), ROOT also gives access to mounted drives' folders that do not appear in choosers due to atypical mounts (more on this below). Because PC is usually a better choice for content, ROOT can be disabled in the Config tab if unused.
Internal on-phone storage comes in multiple flavors, with differing access rules and longevity. The most useful of these are made available as PHONE and APP in the Main tab's choosers:
In the minus column, APP will likely grow less accessible in future Androids. Worse, it is automatically deleted if you either clear this app's data in Settings, or uninstall this app without opting to retain its storage in the uninstall dialog. Please use APP with care; it can be disabled in the Config tab if you use only PHONE storage.
This category includes both SSDs and thumb drives attached by USB port. On all platforms, your drive's name shows up in the app's folder choosers (e.g., MYSSD). The name comes from your drive's label, if set; if no label is available, the name is a serial number or generic title which depends on the host platform (more on this ahead).
If you attach more than one drive, each drive's name appears, and USB hubs work in this app on both PCs and Android. Almost anywhere goes for content folders on such drives, though the drive's top level makes selections easier. Exception: if you're using Android 10 or earlier, your options in this category are constrained; see the special case below.
In addition to PC, phone, and USB-drive storage, you can also select and use microSD cards, optical disks, network drives, and cameras as FROM or TO in this app, if the host device makes them accessible (technically, as mounted drives). Generally, Android phones support microSD cards and cameras, and PCs support all four media types. Here's a brief rundown on each.
While the preceding covers most usage, there are three exceptions worth calling out here:
/Volumes, Linux checks /media and /mnt, Windows inspects mapped drive letters, and Android tells the app where it has mounted drives. These are the norms for each platform, and generally work well.
As a fallback option on Unix-based devices, you can also navigate to any drive's mount location from the ROOT folder, even if the drive is not called out at the top of folder choosers. This generally applies only to atypical mounts on macOS and Linux; Windows has no system-wide root, and Android's system root is inaccessible on unrooted phones. See also platform coverage in App Packages.
com.quixotely.usbsync in the drive's top-level Android/data. Updates anywhere else on removable drives are not allowed by these older Androids.
In practical terms, this means that on Androids 10 and earlier, you should host content in this specific folder on removable drives if it will be either backed up from your phone, or synced from your phone to your PC. Content used only in PC-to-phone syncs need not follow this rule on older Androids because reads work everywhere, and Androids 11 and later have no such constraints. Either way, this app will always warn you if you select an invalid removable folder for Main-tab actions that may modify it on older Androids.
For more background on storage types and rules, please see the GUI Guide's coverage of the folder
chooser.
This last section dives deeper into additional topics that you'll find important as you start using this app. Some of the topics here are covered further in other parts of this app's docs, as noted along the way. In this section, you'll learn about:
Because syncs run in just one direction, you'll want to make changes on only one device at a time. Designate one device as changeable, and sync its content copy to other devices before making changes on them. The advantage of this policy is that you can't accidentally lose changes if the same item is changed differently on two devices in between syncs. If you inadvertently change content this way, you'll need to resolve the differences manually before resuming syncs with this app. Inspect differences with the app's SHOW to find and fix any offenders before running a SYNC.
You can mod both the appearance and behavior of this app in a variety of ways, in its Config tab. This tab describes available settings, which are saved between app runs if you tap the tab's "Save Changes" button. As noted earlier, the app also saves Main-tab FROM and TO paths automatically after an action run, so you don't need to reselect. For finer-grained Config details, please see the GUI Guide.
Although this app runs on both PCs and Android, some exotic content items may not be fully portable due to interoperability constraints on some devices. The good news is that nearly all content consists of normal files and folders, which can always be processed by this app on all devices without loss or error. If your content follows this norm, you can safely ignore most portability concerns.
Rarer items such as symlinks and Unix permissions, however, may not survive journeys through devices which cannot store them. In this app, Unix permissions are copied to the extent allowed by the destination, and symlinks are skipped with logfile error messages when copied to devices that don't support them. This rule applies to both the SYNC and COPY actions in the app.
While some platforms (e.g., macOS) silently forge symlinks with simple files, this hack can fail in some later usage contexts, and would yield perpetual file-type differences if used by this app. Your best option is to omit symlinks in content folders which may be copied to less-supportive devices. For more info, see the Tech
Note.
Some filenames created on Unix (and some Android storage types) can't be stored on all devices either, but these can be automatically adjusted to be portable with the Main tab's NAME action. For more details, please see the full User Guide's coverage of the NAME action here; use this action's report-only option to check before changing.
In addition, this app's Config tab includes an option, enabled by default, to skip platform-unique items that don't belong in cross-platform content (e.g.,
Main-tab actions are run one at a time; you can't start another until a running action finishes. Once started, they never block the app's GUI, and always continue running both if you navigate to another app, and if your screen blanks on Android due to timeout or power-button press. This means you can freely use other apps and turn off your screen without pausing a long-running action in progress.
The mode used to run actions varies by platform. You can simply use the defaults and don't need to know about processes and threads to use this app. Because you can choose modes on Android though, it may help to know the basic differences:
Android foreground services post a notification while running, to let you know when an action finishes. Please allow notifications when prompted by recent Androids on the first action run. On some phones, this mode may also minimize the odds of an app kill or stop for battery or memory management.
Android threads do not post notifications, and are enabled by unchecking "Run Main actions..." in the Config tab. They are forced on in Android 8 for implementation reasons, but are otherwise not required. Actions run similarly fast in both Android modes, and as quick as equivalent command lines in the Termux app. Threads, however, are a fallback option if a future Android disallows foreground services for this app.
Also on Android, the app doesn't allow itself to be closed with a Back button on the Main tab when an update action is running, because this could harm your content. Else, a thread would be killed with the app, and a service would keep running but be impossible to detect reliably on app restarts. To unconditionally close the app and any running action, use a swipe on your phone's Recents (i.e., open apps) display instead.
Tips: on some Android devices, turning on the Logs tab's WATCH to monitor action output can make the action run significantly faster, due to Android's scheduling policies; this may yield a 10x speed increase on some phones, but has no impact on others. See also the in-app About tab's Android note about battery optimizations; no issues are known and multi-hour runs for very large content work well, but you may need to change power settings on some phones if this app's actions are killed.
See also the User Guide's App Packages for Android memory, speed, and power notes, and its Tech Notes for more on Android app kills and stops.
On Android, this app requests only:
These last two of these allow the app to access your content folders stored in both on-phone shared storage and your removable drives. Because these are crucial on Android, you'll be prompted to enable these permissions on the app's first run, as well as by folder choosers and Main-tab actions if not yet enabled. You'll also be prompted to restart the app once after granting these permissions, where needed.
On Windows and Linux PCs, this app requires no storage permissions; you can store your content folders in any PC or USB-drive location that you have permission to access. The same is generally true for macOS, but that platform has storage-access rules that are more convoluted and prone to change.
Specifically, macOS will ask you to enable removable drives and certain folders when they are first accessed, and the app's first-run dialogs mention macOS's Full Disk Access permission as an option. Full Disk Access may help the app use items considered sensitive by macOS, but it is not required for typical content folders.
Besides storage, some PCs may require you to give the app permission to run on its first launch. This is a one-time step, described per platform in the User Guide's App
Packages.
Regardless of permissions, this app never accesses any items on any platform unless you instruct it to do so. Moreover, this app holds no Internet permissions, and accesses the Internet only when you ask it to open its own online resources with an app of your choosing.
Last but not least, this app is private by design. It never does anything with your content, except to move it between your own devices, and only on your explicit requests. Your content is never silently changed, broadcast across the Internet, stored on remote cloud servers, or harvested in any way for information. In short, this app respects the fact that your digital content is your personal property — and challenges other software to do the same.
And that brings this usage overview to a close. You should now be able to start using this app to manage your content well. For this app's terms of use, tools used, and other logistics, see its About tab. For more detailed usage info, please move on to the GUI Guide and other sections of the online User Guide.
More Essentials
Changes
Configuration
Portability
.DS_Store files on macOS); see the GUI guide's Config coverage for more info. Though rare and obscure, macOS's Unicode policies may also pose pitfalls for some filenames; see the Tech Note for coverage and fixes.
Performance
Permissions
Privacy
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