Failure to Create RAID Volume
I purchased a OWC Thunderbay Mini with Softraid XT and 4 OWC Mercury Electra SSDs.
I use a Macbook Pro 16 with Big Sur.
When I trying to create a RAID 5 volume this message appears.
The SoftRAID driver is not loading. Big Sur blocks all drivers by default. Did you go to System Preferences/Security and "Allow" OWC as an identified developer? You must do this when installing the driver or immediately after the driver install restart, or the option goes away. Then you have to reinstall the driver again to make this option available.
Most likely that is the cause of your problem.