Hello, I just registered at this forum to post this issue.
This applies to users that have Internet Explorer as their default brwoser or have it installed in their system.
I don't know how this works if you don't have IE installed...
I just found out that if you have the Windows 7 theme "Bing Dynamic" (the one that uses an rss feed), and run CCleaner, the theme will stop working correctly, meaning it will no longer display the pictures downloaded via the rss feed of the theme, this happens because the feed will not redownload files marked as downloaded (blame Internet Explorer for this).
But I found a workaround, in CCleaner -> Options -> Exclude you have to add the folder c:\users\[your username]\appdata\local\microsoft\windows\temporary internet fles
If you can't find the folder you have to go to the folder options in explorer and enable the "show files and hidden folders" or just add a random folder and then change to the folder mentioned below.
Once you add the correct folder right-click the entry and select "manual edit" and add the following to the end of the text \Enclosure\{8EEA3A94-C94E-4379-9B54-FA51A0C655BC}\*.jpg
It will now look something like this:
C:\Users\[your username]\AppData\Local\Microsoft\Windows\Temporary Internet Files\Enclosure\{8EEA3A94-C94E-4379-9B54-FA51A0C655BC}\*.jpg
This will make CCleaner not erase the folder containing the Bing Dynamic image files, and thus the theme will keep updating whenever new photos come out keeping the older ones, but still eliminate the temporary internet files from Internet Explorer.
In the future, if you add more rss themes, or create one yourself that uses an rss feed, you have to find the correct folder name in the "Enclosure" folder in "Temporary Internet Files" and use the method above to add it to the exclusion table in CCleaner.
Have fun!
Johnny_V