I have split my hard drive(s) into six partitions. I used to be able to see all six from My Computer, but today it has has started displaying only two of them, even in the Navigation pane. However, if I enter the name of a missing drive in the address bar, it will suddenly show up in the Navigation pane. This occurs for each "missing" volumes. Then, once I close Explorer and re-open it, the drives have "disappeared" again.
What could cause this behavior?