Hi, I just opened a zip file from a friend of mine, it was an email I was expecting and the contents are what I expected them to be. I scanned the zip file and the unzipped file using clam xav and it came back with nothing. My only query is that when I tried to open one of the jpgs in preview, finder crashed and relaunched including the menubar and all files on the desktop. The computer is working fine now apart from dropping wifi a few minutes ago. Have I made a mistake by opening the file?