Synology Drive is a Dropbox-like application for Synology NASs which has proven to be very reliable for me over several years. For disk space reasons, I needed to relocate the folder on my Mac that is synced to the Synology to an external drive. While this is an easy task, because it involved moving around my most important data, I wanted to follow instructions (so that I didn’t fall into any traps), but couldn’t find any. This is what worked for me.
One way to do this would be to just stop the original sync, and recreate a sync job in the Synology Drive Client app in the new location. I decided not to do this in case there were any local files that had not synced for some reason, or files with sync conflicts where there was a local conflicted copy.
Quit open applications to make sure nothing is reading from or writing to files in the folder hierarchy you want to move. Pause the sync task in the Synology Drive Client app.
Copy the directory to its new location (keeping the original copy for now).
In Get Info, check that the number of items and file size are the same. The file size in bytes won’t match up exactly (because reasons?) but it should be close enough (the difference for me on ~7GB of files was ~8kB).
Check the sync settings of the sync task in the Synology Drive Client app, then delete the task (the app won’t let you create a second task syncing the same remote directory) and set it up again as before, but pointing to the new location. Make sure you deselect the ‘Create an empty “Synology Drive” folder option’, unless you want it. Check the advanced settings to reinstate any custom settings (e.g., any excluded locations, or the option to sync hidden files).
The client app will look like it’s re-syncing everything (i.e., the ‘Recently Changed’ tab will show a rapidly-scrolling list of files) but looking at the network tab in activity monitor, it doesn’t look like it’s syncing based on the volume of data transferred–likely it’s just running through each file and checking that it is already there.
Check that everything looks OK, the new sync is, then delete the files in the old location. If you want to keep them around for a while, rename the parent directory, and be vigilant that you don’t accidentally edit files in the old hierarchy (e.g., by selecting from a ‘Recent Files’ list in an app or from a Spotlight/LaunchBar etc. search).
Make sure you update any shortcuts/side bar entries to point to the new folder hierarchy.