Indexing not running in Windows 8.1

1. On your keyboard, press the Windows logo and the letter R. It will launch the "Run" box.
2. Type in "regedit"
3. Now look for this string, HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Search\FileChangeClientConfigs
4. If you found it, right click on the folder and rename it to: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Search\FileChangeClientConfigsBAK
5. Close the Registry Editor and rebuild your Index

As others have commented, the indexing of email in Windows 8.1 (Using Outlook 10) is a "real" issue and after several hours of searching I found this solution thread and indeed it worked immediately. Indexing in Outlook started! It does not require a reboot.   

Thanks Kruger and others that suggested this rename fix to the Registry.  For those concerned about touching the Register: Just follow Kruger's directions and you will be fine.  There is one caveat, however, I won't know if it is a permanent fix for "awhile" will I?

My Windows Search and indexing was failing to start, and I was able to fix it by following the steps here:

http://www.kapilarya.com/fix-windows-search-service-failed-to-start-in-windows-8-1

May be worth a try.

I should also add that I found some pages saying this can be cause by registry cleaners, so you may also want to prevent them from starting and running automatically.

I suggest not to run or open programs (uninstalling it would even be great) like system mechanics or registry cleaners, this type of pograms will delete healthy registry strings. Personally, I don't recommend registry cleaners or such.

Update on my situation (your results may vary). After consulting with Microsoft and Iolo tech support, I now know that I am missing vital registry keys. Apparently this is a known issue with Iolo System Mechanic 12.5 for which there is currently no fix. I did not have a restore point old enough to roll back the damage. Therefore, the only solution for me is a tedious refresh of my system. Because I started with Windows 8.0 and upgraded to Windows 8.1, I had to pay $15 to get a refresh disk for Windows 8.1 from Microsoft.

Both Microsoft and Iolo assure me that once I refresh my system, indexing will work again - and I will have to reinstall all of my software. I think I will leave off Iolo System Mechanic for now.

The renaming of the Config file worked for me.

I was having the same problems as others in this thread.  Searching my PC and the messages I could see that the problem was that my index file itself was corrupted or damaged so that the SEARCH would not start.  Since it would not start, I had the Advanced Options greyed out and hence could not change the current search location.  By renaming the registry file and effectively hiding it from the operating system, the search started and I could name a new location.  Now the PC is rebuilding the index at a new location that I can examine.  I hope my PC does not have a relapse!