When I tried to extend the search properties that my query needed to fetch I got the following error: “The property does not exist or is used in a manner inconsistent with schema settings”.
I  opened my trusty ULS viewer to see what error SharePoint was throwing and I found the following error: “SearchServiceApplicationProxy::Execute--Error occured: System.ServiceModel.FaultException`1[Microsoft.Office.Server.Search.Administration.SearchServiceApplicationFault]: The creator of this fault did not specify a Reason. (Fault Detail is equal to Microsoft.Office.Server.Search.Administration.SearchServiceApplicationFault).”

Notice the part I underlined: “The creator of this fault did not specify a Reason” don’t we love the error handling of SharePoint :).

So I googled the issue and I found 2 reasons why I got these errors.

First : If you are using a custom metadata property be sure it’s created in de Search Service Application. After you created the property do a full crawl.

Second : If you are using a standard SharePoint property then we need to be sure we can actually use them. Not all properties can be used for search results. To know what properties can’t be used you can use this little command in PowerShell.

Get-SPEnterpriseSearchMetadataManagedProperty -SearchApplication "Search Service Application" | where {$_.Retrievable -eq $false} | select name

It will display a list with the property names you can’t use. If you want to use these properties you have to create a custom property with the same fields that are mapped with the original metadata property.

Source: http://www.sharepointanalysthq.com/2011/01/refining-on-content-type-in-sharepoint-2010/