I have a serious problem with high CPU (100%) which is definitely related to Outlook 2013 and probably the search indexer.
The computer will be running normally (5-10%) CPU but if I start Outlook within an hour or two CPU usage will be 100%, even though Outlook itself is only occassionally receiving email. When I exit Outlook the CPU usage will drop below 10% without my doing anything else, although this make take 20 minutes or more. When I am experiencing 100% CPU I notice that the taskmgr itself may be showing 30-50%. An initial look at the Resource Monitor (CPU and Disk) has not given me any further clues.
I also notice that when looking at indexing status sometimes it will say 100,000+ items indexed and Indexing complete. At other times it will say 200,000+ items indexed and either Indexing complete or indicating it was still indexing. This seems unrelated to whether Outlook is running.
Deleting and rebuilding the index
Running chkdsk on the hard drive and again deleting and rebuilding the index
Running ScanOST and ScanPST on the Outlook data files and rebuilding the index.
Running Repair on the Office 2013 Pro installation
I would like to avoid having to do a clean install, but I am reluctantly coming to the conclusion that this may be the best option.