So the specific drive i'm trying to remove is a good drive. I've removed other drives in the process (and added them back) and i haven't had any issues. I've tried to reboot several times but that hasn't fixed my issue. Generally the 1st time i try to remove the drive i will get the error in the attachment. If i try again (until i reboot) i will get the following error "Error Removing Drive - The process cannot access the file because its being used by another process". Generally when i try to remove the drive i have chosen "Duplicate files later" option. I of course don't want to check the "Force damaged drive removal" since its not a damaged drive and i don't want to loose data. I have tried without selecting the "duplicate files later" option but it still fails.
Info:
Stablebit DrivePool version 2.1.1.561
Windows 10 Creators Update x64 Enterprise