of course the portable drives are only for storage, never used as a system drive or containing another system, there are only files like music, videos, and pictures, no files are assigned to synchronize with other locations or cloud, and I cannot think of any software that is occupying the drive. The longer I leave it connected to the PC, the more likely it is that it "cannot be ejected or safely removed", returning with error notification windows that we all know, and then, the drives will even get started spinning up again. No file is being copied or transferred, executed or uploading to anywhere at the time.