I've been using XCode for development in C++ for several years. Suddenly, today it started having the following problem: Any time I try to compile my code, (even if I just finished successfully compiling it), it spends several minutes running CLangStatCache. This is according to the result of "Perform Action... Build with Timing Summary". Furthermore, if I first delete the ".../DerivedData/SDKStatCaches.noindex" folder, the problem goes away and it compiles immediately. However, it creates a new folder with a 32 Mb file in it, and then has the same problem the next time unless I delete that folder again. I do not want to have to delete this file every time I compile my code. Is there some way to turn this off? What happened that is different today from any other day in the last several years? I did just download and install the latest System software update, including XCode... Did that break something?