System Mechanic 5 acting goofy

Late last night I started running System Mechanic 5's ''Find and Remove Junk'' function. I used the program's default filter to find files such as *.err (error log files), *.fnd (explorer search files), *.tmp (temporary files), and more. After about ten minutes of searching, the list of junk files exceeded 7,000, and was just 3/4 finished (according to the SM5 progress bar). So I canceled the search and went to bed.

Today I tried the search again, but this time I told SM5 to look for just one type of file - *.err (error log files). I figured that if the number of junk files found were more managable, I wouldn't have to spend much time deciding whether or not to delete them. So I set SM5 and let it run.

After about an hour I returned to find SM5 had found 25,400+ files but the search was only 1/4 of the way completed. Remember this was supposedly looking for only one type (of a fairly uncommon) file. So again, I cancelled and decided to ask here about this.

What do you think is up with System Mechanic? Is that junk file search function reliable? Moreover, both times I tried searching I noticed that some of the file types returned were different from those I'd set it up to look for.

I mean, both searches returned file types such as .dbx, .wpd, tif, and many more files that are not even on the SM5 search check list. Also these files were annotated with the following remark: ''File meets search criteria because it is located within a user-specified folder where all files therein are candidates for removal''. This isn't true because SM5 doesn't ask what folders to search in, it only asks you for what types of junk files to look for.

I'd like to clean up some junk files on my computer and SM5 has seemed to work well for its other functions. Is the SM5 junk file search function unreliable - and maybe dangerous?