Why so many "created shadow copies at a time"

I usually delete all but the most recent shadow/previous versions when I tighten up my drives usually daily or every few days. Today when I looked at the previous versions screen both with 7 and vista there are multiple versions sometimes 6 or more within a few minutes.. See pic... I didn't install anything during those times nor update anything... Any thoughts why this happens occasionally?

Sometimes this is caused by defragmenting programs. If you're running a defragmenting program, simply clear your system restore/previous versions after you defragment.

You can also limit the amount of space system restore and shadow copies can use through their settings.

Start > Right Click Computer > Advanced System Settings > System Protection Tab

Thanks, I will check how I have the defrag program setup to run and I am not using a 3rd party program just the windows program. If it is the defrag program doing that ( I wouldn't have thought the standard windows defrag was THAT efficient ) it does seem a bit over the top to create 3 in a minute...

Previous Versions monitors the change of multiple files, every file change ripples up the file system tree. There fore you will have have several versions.