Did you were developing with SharePoint 2010 and found this error when working with Search Query?
This seems WCF service, isn't it? But you have no clue about the real problem, only a short "Property doesn't exist or is used in a manner inconsistent with schema settings" with an exception in Microsoft.Office.Server.Search.Query.InvalidPropertyException Stack = at Microsoft.Office.Server.Search.Query.FullTextSqlQueryInternal.Execute() .
Jsut don't get mad, we found that this exception (InvalidPropertyException) is related to a managed property that doesn't exist. So you should review the query and find if there are any missing managed properties.
Shouldn't this error be more descriptive?