Important: make sure that by default a sync doesn’t throw any error. Below you will find the most common causes for sync errors and tips on how to solve them. Don’t simply ignore all errors, or at some point you might risk dismissing new errors about files important to you.
When an error happens, the sync will try to continue until the end, processing all the remaining files. If one of the bases is disconnected, the sync will stop.
To view the error message, click the error badge that appears on the right side of the sync item, or select Show sync errors from the context menu. This will open the Activity log window, which contains all messages related to the file operations performed during the past syncs, as well as all errors. (The Activity log window can also be opened from the Window menu in the main menu bar, or from the status bar menu.) Selecting a log shows a more detailed message in the text area at the bottom of the window.
Errors can be marked as solved from the context menu of the Activity log window. Errors are solved automatically when starting the sync again or when they are removed after they reach the maximum log age (which you can set by clicking on the three dots button in the toolbar). When all errors for a sync item are solved, the error badge on the right of the sync item is dismissed.
If there are any unresolved errors, the status icon shows an exclamation mark. If all errors are solved, the icon returns back to the default one.
Notifications
SyncTime always sends system notifications when an error occurs as well as when a sync completes successfully. By default, macOS hides notifications automatically after a short amount of time. To keep notifications visible until explicitly dismissed, you can change the notification type from Banners to Alerts in the System Settings.
Note: system notifications sent by an app are automatically hidden by macOS if the app is already active.
System files
A common source of errors are hidden system directories like .DocumentRevisions-V100, .Spotlight-V100, .TemporaryItems, .Trashes or .fseventsd. These directories are usually located at the root of a device or in your home directory.
If the error happens on the source, it probably means that you’re trying to backup the entire filesystem (including system directories like /Library or /System which usually don’t hold personal files), your entire home directory, or the root of an external volume. 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.
Privacy settings
Another source of errors can be missing permissions for accessing privacy related files like your Photos library, Contacts, Calendar, Reminders and user directories like Desktop, Documents and Downloads. When accessing these locations for the first time, macOS shows 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. To avoid syncing Contacts, Calendar and Reminders, you can exclude the Library directory.
Conflicts
One-way syncs with multiple sources and two-way syncs can produce a conflict error when, between syncs, a file is modified on more than one base, in which case it cannot be determined which file should be preserved.
A source of unexpected conflicts are .DS_Store and .localized files which are automatically created by macOS. Thumbs.db and Desktop.ini are created by Windows. Usually the best solution is to exclude them with a filter.
If you’re unsure why two files are in conflict, you can show them in the Finder by selecting the conflict error in the Activity log window and clicking on the file paths linked in the text area at the bottom. After selecting a file in the Finder, in the main menu select File > Get Info (or press Command-I). In the Info panel you can compare the file size and modification date, at least one of which should be different between the two conflicting files. To resolve the conflict, choose which file you want to keep and copy it over the other file, and run the sync again.
Hint: you can toggle invisible files in the Finder by pressing Command-Shift-.