1. Select "Defrag and Optmize" disk instead. It'll take much longer though. Not to mention that your disk might still not end up fully deframented. Read below for more information.
Originally Posted by kairi033
2. Yes, you cannot do that unless you want to run into problems with defragmenting your disk easily.
3. Yes, but you need sufficient space on another disk and patience. Move all your data + games off your USB disk, quick-format your disk and then move your data + games back on all at once.
SCPH-10000 S. MINOKAMO v1.01 (Defunct)
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DESR-5100 S. EMCS