Everytime I change my external usb drives I have to got to the repository section and select "populte". Otherwise the backup job fails with "Error: Backup repository is not accessible." I have selected the option that this repository is backup up by rotated hard drives. The system is a Windows Server 2012 R2 and the usb drives are accessible at the Windows Explorer. The OS is Windows Server 2012 R2. The usb drives are encrypted with bitlocker but they unlock automatically when they are connected to the server.