I'm sure that this applies to all versions of Windows, but since I'm running Win-7 Ultimate, 64-Bit, I figured I'd post it in the Win-7 forum. Every time I ran Windows Disk Cleanup two files were created in the C:\Windows\Logs\CBS directory. One is DeepClean.log and the other is CBS.log. If you already have a CBS.log file the information will be appended to it. Since I've created a routine to delete the potentially gigantic CBS.log file on a daily basis, the Disk Cleanup utility just created a new CBS.log file. More on that if you are interested here: http://forums.mydigitallife.net/threads/64982-Just-plain-weird-gigantic-CBS-log Anyway, every time I ran Disk Cleanup it created a 140Mb CBS.log file. I just deleted it and didn't think much about it. But today I decided to take a look at it for the fun of it. What I discovered surprised me. The log file has 611,000 lines in it. But even more surprising was the time it took to create it. The time stamp at the beginning was 09:07:07 at the time stamp of 09:08:33, it took a little over 1 minute to write 610,991 lines to the log file. Then it kinda took it's time for another 10 minutes to finish up with the last few lines. So what does this all mean. It means that in the time it took to read this thread, Windows could have written a half a million lines to some log file someplace. And if there was a malicious program let loose on you system, you would be hard pressed to limit the damage it could do, at least in human reaction times. Chances are YMMV depending on your system, speed, and configuration. But next time you decide to run Disk Cleanup, delete the CBS.log file and see what turns up and how it compares to mine. .