I seem to be missing ~100GB off my hard drive. I don't know where they went.
Last time I checked, I had ~150GB free. Last night I happened to notice the red bar, looks like now I have 42GB free. The only thing that happened since then is Windows updates and installing a gift game I got on Steam that took up less than 1GB.
Disk cleanup said it could clear some 500MB. Not quite enough. Getting it to count Windows update files, it said 6GB. That's better, BUT THERE'S STILL 94GB UNACCOUNTED FOR.
Has anyone ever experienced this?
Try SpaceSniffer or TreeSize to see whats on the drive.
I guess I'll look into those...
For visualizing disk space taken by folders I recommend SpaceSniffer. It's fast, small and doesn't require installation.
Some times you forget to allocate it, or as rfe said it gets corrupted.
It encrypts your files with RSA 2048, which basically means you're fucked if you have important files and don't get the decryption key, or have a quantum computer.
Disconnects PC from the Internet
TBH I've never had a problem like this, but it sounds scary. I would clone the drive to an external, format your HDD, and restore with the clone image.
Maybe also start shopping for HDDs just in case =)
[edit] And then I thought of running Spacesniffer with administrator rights. I no longer have 105GB of "unaccessible space", and now I have 109GB of System Volume Information. So system restore points suddenly decided to take up 100GB. The setting was to allow a max disk usage of 25% of its total capacity, I brought it down to 12% and now my free space is at 96GB. I'd say it's a bit better.