Yesterday I noticed that I could no longer filter emails (the last known time I used it was last week, prior to the issues I experienced outlined http://www.geekzone.co.nz/forums.asp?forumid=45&topicid=114233)
Having done a Google search, I tried disabling and then re-enabling Windows Search.
I have now tried doing a repair on Office Professional Plus 2010, but the problem still persists.
Windows Search Email Indexer is disabled in the Add-in section of Outlook.
Both email accounts in use are POP (clear.net.nz, and massey.ac.nz).
I know recently there were security updates for Office 2010 which were installed without issue; whether that has anything to do with this is unknown to me.
I run Windows 8 Pro 64-bit.