Multiple sources, destinations or bases

In the General tab of a sync item’s settings, where you can define the source and destination of a one-way sync or one-way move, or the two bases of a two-way sync, you can define additional bases by clicking on Add more bases and then on the + button underneath the list.

For more information on the individual sync types, see Sync types.

One-way sync / One-way move

Multiple sources will be virtually merged and mirrored to all the destinations.

Files with the same name that are on different sources and have different modification dates or sizes are considered a conflict, causing an error to be logged. If a file has identical copies on two or more sources and only one of them is modified, all the old versions on the other sources would also need to be manually replaced.

A file on the destinations is deleted only if it is not present anymore on any of the sources.

Two-way sync

A two-way sync always behaves the same, regardless of how many bases it contains. In particular, between syncs, a file may be modified or removed only on one base, otherwise it won’t be possible to determine which change should be mirrored to the destinations and a conflict error will be logged.

Sync schedules

The sync schedule can be modified in the General tab of a sync item’s settings.

  • Manual: the default. The sync can only be started by using the toolbar or menu commands or triggered as a dependency by another sync.
  • Automatic: the sync is run whenever the source and destination become available. Once an automatic sync has been completed successfully, the next automatic sync will run after at least the source or the destination are unmounted and mounted again, the app is restarted, or the Mac wakes up from Sleep. The sync can still be started manually at any time.
  • Every hour: the sync is run every full hour.
  • Once a day/week/month: the sync is run at the end of every day/week/month at midnight.
  • Custom: add any number of periodic time intervals. You can choose between:
    • every hour at a specific number of minutes and seconds
    • every day at a specific time
    • every specific weekday at a specific time
    • every specific day of month at a specific time

If the source or destination volumes are not available at the scheduled sync time, the sync is run as soon as they become available.

Force quit

When SyncTime, or any other app that does not appear in the Dock, hangs, it won’t be listed in the Force Quit window ( > Force Quit). Instead, follow these steps:

  1. Open the Activity Monitor app (from /Applications/Utilities).
  2. Type the name of the app in the search field.
  3. Click the Terminate button in the toolbar (with a cross icon) and confirm the alert dialog that appears afterwards.

Launch at login

In macOS, you can select any app to be automatically launched at login.

  1. Open the System Preferences.
  2. Select Users & Groups, then navigate to Login Items.
  3. Click on the + button. In the open panel, select the app that you want to launch at login and click Add.
  4. If you want to app to be hidden when launched, enable the corresponding check box.

Backup strategy

In the Advanced tab of a sync item‘s settings, you can choose whether files that are overwritten or removed should be moved to the trash or a custom folder.

You can select a custom backup folder for each destination base of the sync item. A custom backup folder must be on the same device as the corresponding base; if inside the base itself, the backup folder will be automatically excluded.

When a file is moved to the backup folder, the current timestamp is appended to its name. 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.

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

In the sync item’s settings you can define a list of groups the sync item belongs to. The popup button on the right side of the main window toolbar shows a list of all groups that is automatically updated whenever a sync item’s groups are modified. By selecting a group, you can filter the listed 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 beside 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, the sync will try to continue until the end. If one of the bases are disconnected, it will stop.

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 happens on the source, it usually means that you’re trying to backup the entire filesystem (including system directories like /Library or /System which usually don’t hold personal files) 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 these system items, you can either exclude hidden files or selectively exclude the system items. If, on the other side, the error happens on the destination, it usually means that the destination is the root of an external device: in this case, in order to avoid these system-created files, you can create an empty directory on the root of the external device and use that 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. If necessary, you can exclude the Library directory.

Two-way syncs can produce a conflict error when, between syncs, a file is modified on more than one base; the problem is that it cannot be determined which file should overwrite the other one. .DS_Store files can cause this error when the same folder inside two bases is open in the Finder, in which case they should probably be excluded.

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 some cases, the problem can be solved by 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.