DF 1.17 wiped all recovery points - not happy

Ran DF 1.17 today on Vista x64 SP2. It wiped out all but 1 recovery point (which I think DF created before defrag).

Their help file says about losing restore points

I ran Defraggler on my Windows Vista PC and now I've lost one or more System Restore points.

This is a known issue with Windows Vista and third-party defragmentation tools such as Defraggler. The problem occurs when the amount of disk space set aside for System Restore is too low.

*** Only problem is, I have PLENTY of free space on C: . Vista Help say,

"System Restore might use up to 15 percent of the space on each disk."
Before defragging, I know it had at least 33% free space (don't know exact GB free out of total). That's WAY more than enough free so DF shouldn't erase recov pts.

AFTER defrag, have 21.3 GB free out of 50. 15% of 50 GB = 7.5 GB, so no way Defraggler needed to erase the RPs, that I can see.

This is 1st time ever happened. I'm thinking has to do w/ either / or this is 1st time ran DF after updating to SP2, and 1st time ran DF v1.17.

Anyone (mods) seen this behavior w/ same OS, serv pack & DF version? Any thoughts / suggestions? Please don't repeat what the help file says.

It says it's a known prob when amt of space set aside for System Restore is too LOW. I always had at least 5 (or more) restore points to choose from whenever I looked. Do NOT believe in this case the reason DF erased RPs was insufficient System Recovery space.