I am having the same problem on a newly upgraded site to 7.1.0. Search always returns no result. The event log seems to indicate an empty or missing directory?
AssemblyVersion: 7.1.0
PortalID: 11
PortalName: xxxxxxxx
UserID: xxxxxx
UserName: xxxxxxxxx
ActiveTabID: 368
ActiveTabName: Search Results
RawURL: /DesktopModules/internalservices/API/searchService/search?search=community&pageIndex=1&pageSize=15&sortOption=0&culture=en-US
AbsoluteURL: /DesktopModules/internalservices/API/searchService/search
AbsoluteURLReferrer: http://www.xxxxxxxxxxxx.org/SearchRes...
UserAgent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/28.0.1500.72 Safari/537.36
DefaultDataProvider: DotNetNuke.Data.SqlDataProvider, DotNetNuke
ExceptionGUID: fbb49482-2e29-4399-9480-37d4fa0939c9
InnerException: Search indexing directory is either empty or does not exist
FileName:
FileLineNumber: 0
FileColumnNumber: 0
Method: DotNetNuke.Services.Search.Internals.LuceneControllerImpl.CheckValidIndexFolder
StackTrace:
Message: DotNetNuke.Services.Exceptions.SearchIndexEmptyException: Search indexing directory is either empty or does not exist at DotNetNuke.Services.Search.Internals.LuceneControllerImpl.CheckValidIndexFolder() at DotNetNuke.Services.Search.Internals.LuceneControllerImpl.GetSearcher() at DotNetNuke.Services.Search.Internals.LuceneControllerImpl.Search(LuceneQuery luceneQuery, Int32& totalHits) at DotNetNuke.Services.Search.Controllers.SearchControllerImpl.GetSecurityTrimmedResults(SearchQuery searchQuery, LuceneQuery luceneQuery) at DotNetNuke.Services.Search.Controllers.SearchControllerImpl.GetResults(SearchQuery searchQuery, Int32& totalHits) at DotNetNuke.Services.Search.Controllers.SearchControllerImpl.SiteSearch(SearchQuery searchQuery) at DotNetNuke.Web.InternalServices.SearchServiceController.GetGroupedDetailViews(SearchQuery searchQuery, Int32& totalHits, Boolean& more) at DotNetNuke.Web.InternalServices.SearchServiceController.Search(String search, String culture, Int32 pageIndex, Int32 pageSize, Int32 sortOption)
Source:
Server Name: GENERIC181