I have a fairly new install of Windows 7SP1 and applications that hadn't changed much on a 500Gb (ok, 465Gb) SSD. All told, these used about 270Gb. The disk is a Samsung 850 EVO SSD, 500Gb purchased new with a fresh install of Windows last December, that ran without a hitch until a few weeks ago. Thus, there are no previous Windows installations, hidden partitions (besides swap, possibly), etc. NTFS formatted disk.
A few weeks ago, I basically ran out of disk space. I ended up having to recover some files which Windows wiped out doing a System Restore. Since then, I've only had about 20Gb free. In other words, there's roughly about 170Gb missing. I've done all the obvious stuff:
- Used Windirstat and other tools to verify that I'm only using about 270Gb
- Turned off System Protection
- Never had Indexing on - verified off
- No crash dumps
- Pagefile is 8Gb
- Disabled Hibernation, which I never use
- Virtually no temp files
- Disk cleanup came up with virtually nothing
- SSD is not over-provisioned
- Checked for ADs. About 100 found taking 32 bytes each on disk.
There are no hidden partitions that I can find. chkdsk and sfc came up with nothing. Apart from checking for data streams, I'm out of ideas.