[Roy Dennis]

The only place I know of where it stores any tempary files is in the Quarantine folder.
The only other way I can think of to find where it may have stored them is using windows search feature and type some file names in that you think it may have stored and see if it finds a folder with these files in.

As you say you clicked the rescan folder when it started filling up your hard drive I wonder if it has doubled up files in that folder, can you remove that folder by using the exclude folders button in the rebuild database dialog.
Now hold your pointer over the folder and a pop up should tell you the size of it so make a note of it.
Then open that folder in explorer, right click in the folder and select "Sort by" then "Type" if you can't see "Type" select "More" and a dialog shows with tick boxes for different items, Find "Type" and tick the box for that item.
Now right click in the folder again and select Sort By then Type.
Now this should show all the files sorted in mp3, cdg and kmh which will make it easier to delete all the kmh header files as they are all together.
After that use your pointer on the folder again to check the size again.
Then look at the mp3 files and make sure there are no duplicated files, if there are they would probably have a (2) in the file name.
If there doesn't appear to be any duplicates I'm at a lose.
You can try re indexing this folder now that you have removed all the kmh header files but I'm a bit stuck at the moment.
I should submit a help ticket to support you can access that from Hoste/Help/Online support.
They don't work weekends but they will see it Monday.