I too was able, with your VI, crash LV v7.0 on my system. I followed Ben's suggestion and removed the null string and was able to then set/clear the case-insensitive matching, even after I later re-added the null string. Whenever I have reported problems of this nature to NI they have always attributed them to a "corrupt VI" because, while they have been able to reproduce them with the VI I have provided, they cannot cause it to happen with a VI built up from scratch. Blame it on the Gremlins!