In disk management, right-click on the drive and choose Properties. The on the hardware tab click the Properties button.
Now you have a window with information and tabs. Click the Volumes tab to see what's there, clicking the Populate button if nowt comes up.
See what that does. If there's an actual problem with the drive this should indicate as such. Failing to unmount the drive before unplugging it shouldn't frag a drive though, just potentially lose data.