USB flash drive showing half full

I recently bought a Corsair Voyager 8GB flash drive. I've put some files on it, but just deleted them all, and it now shows that about 3.5GB is full and only about 4GB is free. Could there be some kind of hidden files? Do I need to format this for OSX (I'm assuming it came formatted for Windows)? I will mainly be using it to backup my photo cards when travelling, so not sure if I'll be using it on Macs or PC's (whatever is available at friend's houses, internet cafes, etc.).

Thanks for the help!
Brian

You can certainly try formatting it, use disk utility located in Applications > Utilities, click your flash drive then click the Erase tab, I would recommend FAT32 as it can be read on both Windows and OSX.

Hope this helps

- Simon

Plug it back in to your Mac, then empty your trash while it's plugged in. That should do it.

Yes, once deleted from the drive, you need to empty the trash to get the free space back.

Emptying the trash did it! Thanks for the help, I would never have guessed that was the problem!

It is the same with Windows. Removing the drive prevents trash being emptied as it takes the trash with it!