Backup strategy

You can choose whether files that are overwritten or removed from the destination should be moved to the trash or a custom folder.

A custom backup folder must be on the same device as the destination. If the backup folder is inside the destination (or the source for two-way syncs), it will be automatically excluded.

When moved to the backup folder, the current timestamp is appended to each filename. The timestamp has the format yyyy-MM-dd[T]HH-mm-ss+ZZZZ, which is independent of the current system locale and takes into account the timezone as well. This timestamp will be used in order to determine which backup files lie outside of the selected timeframe and are to be removed.

Follow hard and symbolic links and Finder aliases

While following hard links is supported, symbolic links and Finder aliases are not. This is a standard behaviour for sandboxed apps from the Mac App Store and cannot be circumvented.

If you want to copy files pointed to by a symbolic link or a Finder alias, you can create separate sync items taking care of these files.

Confirmation dialog

The confirmation dialog, which is displayed by default for new sync items, shows all the changes that will be applied during a sync grouped by files to be removed (left tab), overwritten (center tab) and added (right tab).

By default, while the name of regular files is always displayed in black, names of directories can be grey: in the Remove tab, grey directory names won’t be deleted (but contents with a black name will) and grey directory names in the Overwrite or Add tab will not be created because they already exist.

The modification date of directories whose contents have changed is also synchronised according to the overwrite policy. An optional dot “•” in the Size column indicates that only the destination date of a directory is going to be synchronised (and no contents are added or removed).

If the option “Always synchronise tags” in the Destination tab of the sync item settings is enabled, files whose tags will be copied will appear in grey and show a dot “•” in the Size column to indicate that the actual file will not be transferred.

Sync item groups

For each sync item you can define a list of groups it belongs to from its settings panel. The popup button on the right side of the toolbar shows a list of all groups that is automatically updated whenever a sync item’s groups are modified and is meant as a way to filter sync items.

For example, groups could be used to separate sync items based on their destination device, so that when connecting that device you can select the corresponding group and select the sync items all at once. Another possible scenario is when you want to distinguish between sync items needed at home or at your work place.

The status bar menu also contains an item “Sync group” which will run all sync items in the selected group.


Sync items can be dependent on each other. In the Advanced tab of a sync item’s setting, you may add a dependency by selecting the “+” button in the respective text field or by typing a sync item’s title.

When starting a sync item which has one or more dependencies that haven’t been completed yet (i.e. they have no green badge), those will be run first. As soon as all dependencies are successfully completed, the sync item will start running. If a dependency encounters some errors or is canceled, the sync item will be delayed until the dependency is completed.

You may create dependency chains as long as they are not circular. For example, sync item A can depend on B which in turn can depend on C, but C cannot depend on A since it would create a circular dependency. Sync items causing a circular chain are automatically disabled in the dependencies menu.

When starting a sync from the context menu or the toolbar, you may hold the Alt/Option key in order to temporarily skip the dependencies.

Sync errors

When an error happens, unless it is due to the source or the destination being disconnected, the sync will try to continue until the end.

A common source of errors are hidden system directories like “.DocumentRevisions-V100”, “.Spotlight-V100”, “.TemporaryItems” or “.Trashes”. These directories are usually located at the root of a device or in your home directory. If the error is happening on the source, it usually means that you’re trying to backup the entire filesystem (which includes system directories like /Library or /System that usually don’t hold personal data) or your entire home directory. SyncTime doesn’t have enough privileges to access system directories and is not designed to do a full volume backup; it is recommended that you only backup selected directories inside your home directory. If you still think that you need to backup directories containing one of those system items, you can either exclude hidden files or manually select the system items in the Filter tab of the sync item’s settings. If, on the other side, the error is happening on the destination, it usually means that the destination is the root of an external device: in this case, in order to avoid those system created files, you can create an empty directory on the root of the external device to use as the destination.

Another source of errors can be missing permissions for files like your Photos library, Contacts, Calendar, Reminders and user directories like Desktop, Documents and Downloads. When trying to access one of these locations, you should get a system alert asking for permission. In case you denied any of them, you can enable them in the System Settings under Security and Privacy > Privacy. It is discouraged to sync the Library directory located in your home folder because it contains data managed by the system which often requires special permissions. If necessary, you can add the Library directory to the Filter tab of the sync item’s settings. (Note that this directory is hidden in the Finder by default. You can navigate to it in the Open panel by pressing the keyboard shortcut Command-Shift-G, which also works in the Finder, and which will open a dialog that allows you to manually enter a path to navigate to.)

Two-way syncs can produce a size mismatch error when files with equal modification dates have different sizes; the problem here is that it cannot be determined which file should overwrite the other. “.DS_STORE” files can cause this error when the same folder inside the source and the destination is opened in two Finder windows, in which case they should probably be excluded from the sync (see Filter files).

It is always recommended to have a look at the error log, which can be opened by clicking the error badge that appears on the right side of the sync item, or from the context menu. The error log provides information about which files caused the error. Particularly for two-way sync items, it is strongly recommended to sync again by carefully going through the confirmation dialog and making sure that no unique file is going to be copied or removed because of the previous error.

When you sync to another computer, such as a network attached storage (NAS), it can happen that the modification date of a copied file is reset by the destination operating system, which may cause subsequent syncs to report that the file still needs to be synced. In the past, making sure that the network volume has both SMB and AFP services enabled and it is mounted with the same username as the account that you’re currently using on your Mac has solved the problem.

Export sync items

Sync items can be exported so that you can reimport them at any time on any Mac. Exported sync items will be saved as a file with the “.sync” extension.

To export all sync items at once, select “Export sync items” from the status bar menu. You’ll be asked for the location where you want to store the save file. To export only the selected sync items, just drag them onto your Desktop or a Finder window and the save file will be automatically created.

To import the sync items from a previously exported file, you can either double-click it or drag it into the main window. If a sync item with the same title already exists, it will not be imported again. If you want to overwrite an existing sync item with the version from the save file, you have to first delete the existing sync item or rename it so that its title is different from the one you’re importing.

When you run a sync item for the first time after importing it, you’ll be asked to confirm its source and destination so that their locations can be securely stored.

Sync types

The sync type determines how the source and the destination are compared and can be changed in the Destination tab of a sync item’s settings.

Please note that source and destination will be compared each time a sync is run (in particular, each time the app is launched).

Due to a bug in macOS, if the source drive (or the destination drive for a two-way sync) is connected remotely (e.g. via FTP or SMB) and it becomes unavailable during the scan phase, files will automatically be marked for deletion, since macOS doesn’t differentiate between a file being deleted or just being unavailable. For SMB volumes, this issue will likely be fixed by Apple in an upcoming macOS release; unfortunately they have no plans to improve support for FTP volumes. In the meantime, it is always recommended to manually confirm the changes for sync items involving a remote volume.

One-way sync

The destination acts as a backup of the source, which is never changed by a sync. This is the default sync type. Files that exist only on the source are always copied to the destination. Files that already exist on the destination are overwritten according to the overwrite policy chosen in the Destination tab of the settings. Files that exist only on the destination are deleted only if the option “Remove files not on source” is enabled.

Two-way sync

Merge source and destination. Files that are only on one side are copied if they have been modified * after the last sync or deleted if they have been modified before the last sync: this way, deleted files are not going to be restored with the next sync (except for the first sync, where all unique files are copied). If a file exists on both sides and one of them is overwritten, any changes to the other file will be lost since no merging is done inside the files themselves.

One-way move

The destination acts as a mailbox ingesting files from the source. As soon as a file has been successfully copied to the destination, it gets removed from the source.

* If the file is indexed by Spotlight and the “date added” attribute is available and indicates a date later than the last sync date, the file will be copied even if it wasn’t modified after the last sync, which is the desired behaviour. Since this attribute is not always available, caution is recommended when moving or renaming files managed by two-way syncs. If the attribute is not available and you want to add a file that has been modified before the last sync, you will have to copy it manually to both the source and destination or add it to the source while the sync is running in background, otherwise it could be erroneously deleted. You can also move a file to be deleted to the Add list and vice versa from the context menu in the confirmation window.

Please note that due to an issue in macOS 10.12 (Sierra) and later, the date added will not be set on renamed files, so that in two-way syncs they will appear in the delete list by default. In this case, please move any renamed files manually from the Delete list to the Add list from the context menu in the confirmation window. Renaming files while a sync item is watching the source in background is safe. One-way syncs and one-way moves are not affected.

Action after all syncs have completed

You can define whether your Mac should go to sleep or shut down after all syncs have completed and also execute arbitrary scripts.

  1. Open the AppleScript Editor (located in /Applications/Utilities).
  2. Create appropriate AppleScripts by copying the codes given below (or writing your own scripts) into the Editor and saving them on the Desktop with a meaningful name.
  3. Open the scripts folder from the status bar menu by selecting “Once all syncs are completed > Open scripts folder in Finder”. (The scripts folder is located at “/Users/yourusername/Library/Application Scripts/org.desairem.uSync”.) Move the newly created files into this folder via drag and drop.
  4. Restart SyncTime. A menu item corresponding to the file you’ve just created is now visible.



tell application "System Events" to sleep

Shut down:

tell application "System Events" to shut down

Play a sound with a given filename (you may store your custom sounds as well in “/Users/yourusername/Library/Application Scripts/org.desairem.uSync”):

do shell script "afplay /System/Library/Sounds/Glass.aiff"

Play a random sound from “/System/Library/Sounds”:

do shell script "afplay /System/Library/Sounds/" & some item of paragraphs of ((do shell script "ls /System/Library/Sounds/"))

Synchronise in background

You can enable the option “Once synced, keep synced in background” in the Advanced tab of a sync item’s settings. After the sync has been run as usual, files will be automatically transferred as soon as they are created or modified on the source (or removed, if the option “Remove files not on source” is enabled). For a two-way sync, this also applies for the destination.

A background sync will run indefinitely and cannot be restarted until stopping it from the context menu.

Please note that after restarting the app, a sync will compare the whole source and destination again before monitoring for changes in background. While the changes for this first sync have to be confirmed by default, background changes are always applied without confirmation.

Please note that changes on a volume can only be detected when they are performed from the local Mac.