Basically Ccleaner seems unable to delete files such as
1) IE temporary internet files,
2) Windows MS Search.
3) Applications for McAfee anti virus and sometimes other files altho' often it announces 0 bytes have to be removed and then, after another run, apparently has to delete the same files again.
I repeat, is this likely to be simply a glitch on my new computer with Windows 8.1?
Are you running ccleaner either with UAC elevation or the SkipUAC setting (in ccleaner) enabled?
While it should not effect the examples are the temp file (ccleaner) settings set to only clean older than 24 hours (recyclebin and temp directory are the only ones this covers though, I think.
The McAfee maybe isn't deleting because McAfee is using it.