I've been having the same problem with a Vista Home Edition and now with an up-to-date version (3.06.1433). CCleaner wasn't picking up those thumbnail files in Analysis. One person thought the option for CCleaner under Advanced, not to delete temporary files younger than 48 hours, made a difference. I have that unchecked and was still getting the problem. Another person said to make sure that Explorer was closed when you're running CCleaner. I still had the problem. I used the Windows Disk Cleanup and it deleted 18 MB of thumbnail files. Immediately after that, I used Explorer to create new thumbnails, then ran CCleaner, and it was able find the thumbnail files. CCleaner is doing a poor job of cleaning these files and of notifying when it is failing to find any files. I wonder if having thumbnails that pre-date the new installation of a CCleaner update has something to do with it. Or perhaps it can't see files that are too large or too old. At any rate, if you are having this problem, try using Disk Cleanup (under Accessories/System Tools), and I guess wipe your disk to overwrite those cleaned-up files, and see if that fixes it for a while thereafter.