Can SyncTime run while the Mac is asleep?

If the sync schedule of a sync item is set to a time when the Mac is asleep, macOS automatically delays the sync until the Mac wakes up again.

There might be instances where you want a sync to run while you’re not using your Mac, such as if a sync is expected to copy many files that should be available on the next morning. In this case, the only option is to keep your Mac awake until the sync has finished.

In the System Settings, under Lock Screen, you can control when the Screen Saver starts and when the display is turned off after a period of inactivity.

When the Screen Saver starts, the Mac is still awake and syncs can still run. When the display is turned off, the Mac might still remain awake for some time, but can go to sleep as soon as no process prevents it from doing so. To actively prevent automatic sleep when the display is turned off and the Mac is connected to the power adapter, in the System Settings, under Displays, click on Advanced (at the bottom) and enable the option “Prevent automatic sleeping on power adapter when the display is off”.

How do I add my server as a source/destination?

Everything you can see in the Finder, you can select as a source or destination. If the server you want to select isn’t visible in the Finder yet, you can mount it by activating the Finder (e.g. by clicking the icon in the Dock), then select the menu Go > Connect to Server (or press Command-K). You’ll then be asked to enter the server address.

After you click Connect, you’ll be asked to enter the login credentials to the server.

If you would like these credentials to be used automatically when connecting to this server in the future, enable the option “Remember this password in my keychain”. The Keychain Access app (installed by default with macOS) will then store the entered credentials. Unless you activated the option “Do not auto-mount volumes” in the sync settings Advanced tab in SyncTime, these credentials will be used automatically when starting a sync and the server volume has been unmounted in the meantime. (The stored credentials are protected with your macOS account password and are not accessible by SyncTime or other apps: when SyncTime starts the sync, it will issue a mount request to macOS which will then look up the stored credentials without disclosing them and connect to the server.)

After you click Connect again, the volume will be mounted and visible in the Finder sidebar or on your Desktop. You can now select it in SyncTime.

Should the username or password change in the future, the login dialog will be displayed again to allow you to enter the new information. Should the server address change, please mount it by following the steps above and then select it again as the new source or destination in the sync settings General tab.

Overwrite policy


Files on the destination are never overwritten. As long as this option is selected, the destination only contains the first version of each source file.

Overwrite if source file is newer

Files on the destination are only overwritten if the modification date of the source file is newer than the modification date of the destination file. When editing a source file, the modification date is automatically set to the current date and time, which would cause the file to be synced again. When replacing a source file with an older version, that version wouldn’t be synced until editing it again.

The maximum time tolerance setting defines the maximum allowed time difference between two modification dates to be considered equal. The default is 2 seconds. When syncing two volumes that have the same format, a value of 0 should be fine, but when syncing two volumes with different formats, there might be issues caused by the different time resolution. For example, FAT32 only has a time resolution of 2 seconds; in a sync from an APFS volume to a FAT32 volume with a time tolerance of 0, many files would be constantly listed as having changed, even if they have not. The reason is that the timestamp saved on the FAT32 volume cannot always be saved as it is on the APFS volume.

Overwrite if timestamp or size is different

Files on the destination are overwritten whenever they are different from the source. Since it would be too inefficient to compare the file contents, the modification date and size are compared instead.

The same observations about the maximum time tolerance setting apply as for Overwrite if source file is newer.


Files on the destination are always overwritten, regardless of whether their modification date has changed or not.

How can I sync only files with a given extension?

  1. Add a new sync item by clicking the + button in the toolbar.
  2. In the General tab of the sync settings, type a title that describes the sync item. Then click on the first folder icon to select a source directory (in the image below, Documents), and on the second folder icon to select a destination (in the image below, Downloads/txt files).
  3. In the Filter tab of the sync settings, enable the checkbox “Filter files matching any of the following expressions”. Then type the file extension in the text area below (in the image below, .txt) and press Enter. (Alternatively, click on the + button below, select Filename in the popup menu, and double click the expression in the text area to edit it.) To turn the expression from excluded (the default) to included, open the menu by clicking on the arrow on the right and select Include.
  4. Enable the checkbox “Filter following files”. Then click on the + button below and select the source directory that you chose in step 2.
  5. Click the red title bar button to close the sync settings.
  6. Run the sync item by clicking on the Play button in the toolbar.

How can I sync iCloud Drive with another directory?

The iCloud Drive folder which you can access from the Finder downloads files on demand by default, i.e. not all files that you may want to sync are directly available for syncing.

If you try to sync a file that has not been downloaded locally, SyncTime triggers the download during the file copy phase. To ensure that all files are always downloaded locally and be able to sync them without delays, you can disable the option “Optimise Mac Storage” in the System Preferences, under Apple ID > iCloud.

Why is the app interface using [this language] instead of [other language]?

SyncTime currently supports English and German. macOS will launch an app in the first of your preferred languages that is also supported by the app, e.g. if German is placed higher in the list than English, the app will be launched in German . You can change this in the System Preferences, under General > Language & Region.

At the top you can change your preferred languages.

At the bottom you can select specific apps to use a specific language.

Why do some files seem to change on each sync?

The default overwrite policy is “Overwrite if timestamp or size is different”. This option can be changed in the sync settings Destination tab. Most volumes work out of the box with this default setting, but some volume formats may cause files that have not been modified between syncs to be listed again in the confirmation window. For example, during my own testing I noticed that volumes that use the FAT file format (which is primarily used by older devices) don’t allow setting a custom modification date on directories. Unfortunately I couldn’t find any official documentation on this behaviour. It seems that whenever a directory is created, the current date is automatically set and cannot be changed. Hence SyncTime will find that the modification date of a source directory is always different from the one on the destination, trying to sync it each time. A workaround is to use the “Overwrite if source file is newer” overwrite policy instead. Beware that when using this overwrite policy, if you replace a source file with another version that has an older modification date, this change won’t be synced until you open and modify the source file so that its modification date is updated.

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.