I've been unable to find help for this problem on IBM/Lenovo's website, and I'm hoping maybe somebody else has run into this. Since I upgraded to System Update 2, which I had to do, otherwise the update system would not function at all - as it required the update.
System Update Error 742: System Update downloads the file and gets almost through the "installing" progress bar, then a message pops up saying, "System Update" cannot find the source folder. The command line option (/S) must use a valid source folder.
The tech guy at my computer place suggested I call Lenovo, but the last time I did that I got somebody who knew less than I do about computers. Not exactly encouraging.