AppleRAID works, SoftRAID doesn't

I have a theory on what happened. The drives may have been "TRIM"-ing. There is a timer in SoftRAID for how long the application will wait before telling the user that creating the volume failed/succeeded. It took too long to create the volume. When all TRIM functions were completed on the drives, then the volume create process completed normally.

I don't recall enabling TRIM. I'm not sure if it makes a difference with the Samsung 850 pro

Understood, but it could fit the symptom if you had TRIM enabled.

Understood, but it could fit the symptom if you had TRIM enabled.

Having this exact same problem. Uninstalled using app cleaner a few times, tried both the lite and regular versions and still giving me the same error.

Here's the log output:

May 16 1903 - SoftRAID Tool: Creating the RAID 5 volume named "Kramer3" of size 14.6 TB with the following disks: disk11, SoftRAID ID: 06BA67CC1DEF1640, SATA bus 0, id 0 (Thunderbolt), disk9, SoftRAID ID: 06BA67CD4FC80200, SATA bus 0, id 2 (Thunderbolt), disk8, SoftRAID ID: 06BA67CC34477440, SATA bus 0, id 3 (Thunderbolt).
May 16 1913 - SoftRAID Tool: The volume create command for volume "Kramer3" () failed with an error (error number = 31).

Please try again after installing the 10.11.5 combo updater and/or create a new admin account and try again.

Using apps that "clean" your mac can leave some apps, drivers and low level OS X tools in an unstable state. SoftRAID makes calls to tools like disktool to create the file system. This is completely in the hands of OS X at that point.

We recommend you NEVER use any "app cleaner" kind of tool. Most cause more damage than they fix.