Gen 2 4th Bay reported failure, replaced drive is not recognized

I have a gen2 and in the 4 bays, I had a 4TB, 3TB, 3TB and 2TB. Everything was working fine until it reported a drive failure in Bay 4 (The 2TB). I have a 5N2 so I ordered a large drive for the 5N2 and took a 3TB out of my 5N2 and put it into my Gen2. Nothing happens. It doesn’t even sound like it spins up. If I take out the 3TB and replace it with the 2TB, I get a drive failure.

The 2TB is a Seagate drive so I tested it with Seatools and it passed all tests so Seatools thinks the drive is OK.

I don’t have a support contract on this Drobo because it is so old. Any ideas on what to try next? The Drobo is working fine with 3 drives, but now it makes me nervous to put anything important on it.

You can try reformatting the 3TB drive with your OS. If the OS wishes to wipe the ‘unrecognized’ format then allow it. It worked for me once.

Just tried that. Didn’t work. Thanks though.