For the last two builds through 14942 (I'm on the fast ring), I've been having problems where the start button/start menu would freeze or become non-responsive. I've run virus/malware scans (with paid ESET and Malwarebytes) with no threats shown. I will click the start button and either nothing will happen, or the background will come up blank for 30 or so seconds until the buttons/tiles fill in. I then click on the tiles and nothing happens, or the programs open 30-60 seconds later.Odd problem - haven't seen anything like this ever.