For some reason all my mp4 files are now opening with my printer's software. I don't want to uninstall my printer, but I do want my video files to open with VLC. I tried to use the Information window to set VLC as the default program for all files of the mp4 type, but every time I change it, it resets to HP Photosmart Print! The Info window also says it's an "HPIP" file -- is that right or is that why it's opening with HP software? I don't watch a lot of videos, and certainly not many mp4's, but I've checked 3 or 4, all from different dates/sources and they are all having this problem. Interestingly, if I right click the file, it says that VLC is the default (and will open with VLC if I right click and choose that program) but if I simply do the cmd-O or double-click the file, it still opens with HP Photosmart Print. The first time it happened, the video did actually play (why does my printer have the capability to play video files in the first place?) but ever since, it just opens HP Photosmart and the video doesn't even play! Also, I can change the default program to VLC for individual mp4's, but if I click "Change All" then it reverts to Photosmart Print for that file.