I think that the code here shows a bug in Lucene.NET, see http://gist.github.com/1056231. This happens when using 2.9.2.
After some digging I think that it's due to the way it does a Prefix search. The main problem is shown by this code http://gist.github.com/1056242. If the Locale is Danish, this returns FALSE, weird eh!! "daab".StartsWith("da") //false But this works as expected "daab".StartsWith("da", StringComparison.InvariantCulture) //true The line of code that has this problem is the TermCompare(..) function in PrefixTermEnum.cs, see http://svn.apache.org/repos/asf/incubator/lucene.net/trunk/src/core/Search/PrefixTermEnum.cs
