Hi

If you have removed those drive from selection then does resource credentila list those drives still,have you tried making new selection and checked and lastly you can also remove the server and readd it back and then check see if that helps (Removing and Regarding server would cause other confuged jobs and job log to be removed too)

Thanks

What type of job are you running Full, inc, diff... if inc or diff you will see this until the full backup job runs. If your running a full job try recreating and running the job and report back as to whether or not youre still seeing the exceptions.