I recently got a Mac and my friend downloaded Mac OS X v10.6.3 v1.1 for me and put it on a disc so I could install it. I do have some concerns however. First, Apple lists the size on their website as 785.29 MB. The file when placed on the hard drive is listed as 823.4 MB, and I believe 823.5 MB if I right click on the disc. Both of those seem to be a big difference than 785.29 MB. Is this a legit file? How can I tell? Secondly, while my friend also has a Mac I'm sorry to say they don't keep their computer as safe as they should. He doesn't install updates and I think could have that trojan that comes in pirated iworks or ilife, since he didn't buy the program. Would my combo update be infected be infected with a trojan horse or key logger or virus?