I had a notification that disk 2 on my RAID was faulty, and the RAID was degraded.
I bought a new replacement drive (same model as the faulty one), installed it in the NAS, and then added it to the RAID as a spare. The RAID then started rebuilding, and 8 hours later I had a 5 disk RAID5 system back, with all my data apparently intact. Then I tried to save a Word document and got a permissions failure.
When I looked at the Security tab under properties, it show Everyone as having Full Control, but the owner as being N5200/nobody. I tried to take ownership of the folder using my Administrator profile, but it wouldn't allow me. I ensured that the userid on the NAS and my PC were compatible and with the same password, no joy.