If you can't delete an ISO file as the file is open in your System, check if it is mounted as a drive or not. Uses these proven fixes to resolve the issue.

There are instances where users reports getting an error “File is open in COM surrogate” when trying to access or rename and edit a file on Windows Properties.

static System.IO.FileStream Open(string path, System.IO.FileMode mode, System.IO.FileAccess access, System.IO.FileShare share) For my testing, I am using the parameter set that includes the string ...