Unused Space in FAT32 vs. NTFS


New Member
My physical hard drive is partitioned into C: (15.5 GB FAT32) and D: (41.6 GB NTFS). My computer is a Sony VAIO that I bought in 2001, and it was partitioned this way when I bought it. When I run Erase Unused Space on drive D:, there is not much change in the amount of unused space, but when I run it on drive C:, the unused space changes typically from about 2.6 GB to about 3.1 GB. I'm not complaining :) , but I'm curious why the unused space changes by such a larger amount in FAT32 than in NTFS.
It's not that it changes in FAT32 more than NTFS - it's the doing of System Restore. C is your OS drive and contains system restore entries - D probably doesn't. When Eraser fills the disk old system restore entries are removed freeing disk space; since D doesn't have system restore entries no extra space is freed.

I appreciate the information (and clearing up of my assumptions about the file systems). So I'm thinking that, if I change my system restore settings to use less disk space, I'll free up more space for normal use and probably won't see as much of a change when running Erase Unused Space.
Yes, that's correct. But remember that System Restore can be a valuable tool when recovering from crashes! It is also helpful in later OSes since System Restore also controls volume Shadow copies which let you restore files form an earlier point in time. Of course, because of this functionality if your threat model requires high security you may prefer to disable system restore.