I have a WD Elements 2.5 TB USB 2.0 Hard drive. I have been backing up all my files (including very important pictures) on this harddrive for nearly a year now. Recently, when I plug my WD Elements into any one of the three MAC computers I have the disk automatically disconnects. MAC Disk Utility …

That wouldn’t be a bad idea, just in case, you can also run a test with DLG. How to test a drive for problems using Data Lifeguard Diagnostics for Windows