Not sure if I should post my question in superuser, but it looks like the most appropriate place among all StackExchange sites. I have a 16GB Kingston DataTraveler USB drive. When I tried to use it this morning, it showed up nothing in there but yet its details showed that half of the capacity was in used. I tried it with OS X, Ubuntu, and Windows 7 and the results were the same. I tried to create a new folder and it worked. Apparently, the drive is working but somehow not showing my previously stored data. Note that I was still using the drive last night and there wasn't any problems. Following @rob's suggestion, du -h gave me: 16K ./.Trashes 960K ./.Spotlight-V100/Store-V1/Stores/2620683B-A38B-42F4-A247-45CAF4826ADE 976K ./.Spotlight-V100/Store-V1/Stores 1008K ./.Spotlight-V100/Store-V1 1.0M ./.Spotlight-V100 1.1M And, df -h gave me: /dev/sdb1 15G 7.9G 7.1G 53% /media/KINGSTON Confirming what I reported. Anyone got a clue/answer to this issue? Thanks.