With the new transparent Selective Sync feature on OS X Agents, the following error messages may appear indicating some possible misconfiguration in the job itself or mount point.
Failed to mount the folder on the chosen path
Error code SE_FUSE_MOUNT_FAILED
This is a very general error and basically signals that something went wrong. Possible reasons may vary. For example, the agent does not have write permissions in the parent directory, or when trying to mount on an invalid path.
The folder location was unexpectedly unmounted. Restart the Agent
Error code SE_FUSE_UNMOUNTED
Appears if the mounted folder gets unmounted for any reason, manually by a user, forcibly for some unexpected reasons.
Check with the "mount" command in terminal.
To fix it restart the agent either from MC or by the user
Cannot mount folder: the chosen path location is not empty
Error code SE_FUSE_MOUNT_NOT_EMPTY
It's possible to use a pre-existing directory, but it must be absolutely empty. Check for hidden files/folders there. Even agent's .sync directory - remnants from possibly previous job runs will prevent re-using this directory. Better check it with the Terminal app, most likely there's a hidden .DS_Store file that is not visible in Finder even if "view hidden items" is enabled.
There’s already a folder mounted on the chosen path
This error message means the Agent cannot create and use a Selective Sync folder on the file system because there's already a folder mounted on the same path.
The most frequent reason for it is that the Agent failed to properly unmount the folder when quitting last time. For example, the file from the TSS folder was still open in some application when the Agent was closed.
Note, unlike "SE_FUSE_MOUNT_NOT_EMPTY", this error refers to the Job's folder that the Agent was previously syncing. It does not refer to a regular pre-existing folder in Finder.
To fix it, quit the Agent. Open the Terminal app and check with the command "mount" if there's indeed this directory still mounted.
You need to manually unmount it with command umount /path/to/folder, then start the Agent.
Waiting for system extensions to be allowed
This error means that user hasn't yet allowed new agent's system extensions. Here's the guide to resolve the error. Once resolved, error shall go away automatically.
Changing the mountpoint for Selective Sync folder is not supported
This is a pretty rare error and indicates a possible race condition when changing the folder mode from full sync to Transparent Selective Sync. This can only be done through removing the agent from job and adding it back with the new mode, and the error appears if removing was not properly processed before agent was added back. For example, because the agent hanged, was forced to quit (improper shutdown).