Missing Drive Letter


I have a 5N and running Win10 on all devices. I just noticed this evening that one of my “Shares” and assigned Drive Letter (G:) is missing. Well, the Share still exists in the Dashboard, but it’s no longer assigned. When I attempted to reassign it to G:, G: did not appear in the list. I connect the Share to another letter and the files are still there which is a good thing. I’m just trying to figure out where G: went. I rebooted both the computer and the Drobo but it’s still gone.
The only thing different is that I did have a warning a few weeks ago on one of the drives and it had to do some rebuilding or something. I added 2 more drives to max at 5. The 1 drive, while still green and functioning, shows “warning” in the dashboard.
Other than that it’s business as usual.