Can't open files in search results from a mapped network drive on Windows 2012 R2 Standard Server with Windows 7 or Windows 8 clients. File icon is blank too.

I recently implemented a new Windows Server 2012 R2 Standard server running the Essentials Experience Role.   The mapped drives are applied to the client machines using Group Policy.   Typically the users go to any mapped drive in Windows Explorer on their PC, type in their search criteria in the search field in the upper right hand corner of the window and then get a list of all matching files on that drive - Word docs, Excel sheets, PDF's, etc.

But occasionally they were having a very strange issue where the search results appeared but they could not open any of the files when they double-clicked on the files.  No error message was given.  Also, they could not right-click on files either.  The other weird part is that the little icon next to the file name that usually shows the file extension icon (Word, Excel, PDF, etc.) was a blank icon.

I did a ton of online research but couldn't find any help for this issue.  I don't think I've completely solved it yet but I do have a way of getting the search results to start working again.  I found that if I go to the Windows 2012 R2 server, pull up the list of Services and restart the "Windows Search" service, that my search results will start functioning properly on the client PC's - they'll display the proper icon and they can be opened as expected.

So something is clearly wrong with my Windows Search service.  I'm still trying to figure out what causes it to fail but at least now I know how to fix the search results issue in the meantime.  

Please comment below if you've run into this issue and found any other fixes.