Folder not found error (on desktops) or Can't open the destination folder (on mobiles) may appear in either of the following two cases:
1.When you add a folder to Sync and then delete it from the file system (thus, the folder name is still visible in Sync, however, the actual folder has been removed).
2.When you move a syncing folder to another HDD or another logical partition of the same HDD.
Although Sync v2.x supports moving of folders, such manipulations should be done within one logical partition of the disk.
Although Sync v2.x supports moving of folders, such manipulations should be done within one logical partition of the disk.
Possible solutions:
1.If the folder hasn’t been deleted from the hard drive completely but just moved to Recycle Bin/Trash, you can recover it by using the Restore/Put Back option.
2. Click on the error message and point the folder to new or the correct location of the folder.
3. Remove the folder from Sync and then add it again at the new location. However, in this case all previous connections to this folder will be terminated and you'll have to reconnect it to other peers again.
The above steps should restore the connection with the folder and synchronization will be resumed.