Why does the SD card icon still show in File menu after the card was removed?

This information pertains to the original LabQuest.
If you have LabQuest 2, see LabQuest 2 FAQs and Troubleshooting

If you remove an SD card from the LabQuest when LabQuest is asleep, LabQuest will still think that the SD card is there when it wakes back up. You can clear the "phantom" SD card by inserting and immediately removing the SD card after canceling the File dialog.