I am trying to move my unraid boot usb to a new usb.

Created usb using unraid USB creator and used backup zip for file/drive creation

Booted with new drive.  Removed old keys (as instructed in error message) and hit Recover Key button but fails with status code 403 Keyfile unavailable

 

Tried searching forums for what I might be doing wrong, but not having much luck

I think if that is a new USB then you should have your old key file in the 'config' folder so that it offers you the option to transfer the licence to this new drive.

I tired that, but with original keys present the recovery key button disappears and and the only options are to purchase or redeem code

You must leave the previous key, but cannot have multiple keys, alternatively contact support.

Thanks - will give that a try