So I just added a new WD 10TB HDD to my system and precleared it. After a succesfull preclear my two Seagate 8TB HDD's that were attached via a USB dock and until now working perfectly, had the red x next to them and marked as being emulated. I tried a reboot but no change. I powered down and restarted also without luck. Thinking the dock might be faulty I tried another dock, it didn't recognize the drives at all, marked them as missing. I reattached the original dock after checking that it was working on another computer. On reboot the two drives now had a blue square next to them. Couldn't find much info on this apart from UnRAID thinking two new drives had been added. As I had two parity drives I thought that starting the array would rebuild the two 'new' drives so I did so. UnRAID displayed 'Parity Sync/Data-Rebuild' and a percentage in the status bar so I was optimistic. The notification said that Disks 4 and 5 were not ready and contents were being reconstructed. About 54 hours later, those two drives now appear with a green circle but with the message 'Unmountable: No file system'. I haven't formatted them yet. Have I lost 16TB of data? It seems what UnRAID did is recalculate parity for the other three drives that were still OK, so I might not be able to restore my lost data if it's no longer included on the updated parity drives.

 

What should I be doing now? Any chance of recovering anything?  Screenshots taken throughout the process are attached. Running UNRAID 6.4.1

Please post the diagnostics: Tools -> Diagnostics

unovo-diagnostics-20190619-1932.zip

Check filesystem on disks 4 and 5:

https://wiki.unraid.net/Check_Disk_Filesystems#Checking_and_fixing_drives_in_the_webGui

or

https://wiki.unraid.net/Check_Disk_Filesystems#Drives_formatted_with_XFS

 

P.S. using USB array disks is not recommended, both for performance and reliability reasons, they have a tendency to drop out.