Hello,
I confirm that the version of CCleaner 2.21.940 deletes the Common.xcu very important file that contains the user settings (Options> OpenOffice.org> ...)
The Recent Files and URLs are located in the file Histories.xcu can be cleaned with CCleaner safe.
It would be nice if the next version fixes this bug.
Thank you for your very excellent program that I recommend in the french forum of OOo.
http://user.services.openoffice.org/fr/forum/
Best regards,
papayes