It seems that many have a problem with restore points disappearing. See here..
This is possibly the longest thread in MS Answers, and I have read through it because I too had a problem with restore points. What I couldn’t understand was why Windows frequently created them without warning me that there was a problem.
As it turns out, the problem was me.
I ran the Command Prompt as administrator, and typed this line..
vssadmin list shadowstorage
It showed that I did have restore points, but what I didn’t immediately notice was the location. I had originally installed Windows 7 on a 160gb SATA drive but I felt that the drive was not as good as it could be. So I did a fresh install onto a 320gb SATA drive, and then deleted the Windows folder from the old drive which now had the letter G.
With eyesight like mine, the letters C and G look the same in a CP window. The restore points were all being saved to G which still had a 20gb allocation, but the C drive which was also showing as ‘on’ didn’t have any allocation at all.
It does now. There is enough space for three complete restore points, too much in reality, but I want to see if it saves all of them in a usable state. So far, it is looking good..