You need to make sure that the VPP's are being indexed. Take a look at the following blog post:
It's written for CMS 5, but should work for CMS 6 as well.
Thanks for the link, Mari, but I have tried everything in that post, and it still doesn't work.
Check the paths in your x\Program Files (x86)\EPiServer\Shared\Services\Indexing Service\EPiServer.IndexingService.exe.config and se if they are valid. Delete your "index" folders and restart the indexing service. Then your "index" folders should be recreated if everything is ok...
Edit: Damn, I just written what Mari linked to... Ok. Do you have mixed versions of EPiServer sites on the same machine? 4, 5 and/or 6? Then you might want to reinstall the shared components for CMS 6...
Also make sure that the indexing service do have the proper access rights on the VPP folder so it can create the index folder and files.
I think you can see in services.msc (win+r) what identity the indexing service has.
Thanks for the help. It turned out that the LocalService user needed rights on the VPP folder, as Toni said.
My team is using EPiServer CMS 6.0, and when I attempt to use the search functionality in Admin Mode -> Admin -> File Management, I get this error:
VirtualPathProvider 'SiteGlobalFiles', Search Error: C:\Projects\Webportal\Epi\VPP\WebProject\Global\index not a directory
I am relatively new to EPi, and not sure where to start to fix this problem.