I just downloaded OSX Lion today and have been a bit annoyed with a few things. I often have large PDF files for grad school and relisten to lectures on VLC. However, it seems like preview automatically saves these files every few minutes whenever I pause the lecture on VLC.This is annoying because the pdf files are really large and saving them could take one to two minutes. I am unable to take notes during that period. Is there any way where I can disable this function?