Hi I started encountering what appears to be an unusual problem: Windows 7 file Explorer started crashing and automatically restarting consistently on opening or browsing any directory containing Matlab .mat files! Cygwin I looked int blogs and it appear to be happening to others but mainly with media (e.g. mpeg) files. On my machine, .mat is associated to Matlab via the registry but I can not even run file to program association utility as it uses explorer to search for all file extension on the machine so it crashes too. I did not have much luck with the blogs (I already posted issue to Matlab Newsgroup blog) so I wandered if anyone of you has a suggestion how to solve this issue. PS: Cygwin, Matlab and windows commnad window have no problems browsing or reading those directories but wordpad file open similarly crashes. Best George