Can't update my iMac to 10.7.4, every method says file is corrupt.
I am somewhat new to Mac but I haven't had to post on this forum yet so I will try to be as clear about the issue as I can be.
I have an iMac (21.5 inch Mid 2011) and I am running 10.7.3 right now.
Software update informed there was an update available to Lion (10.7.4) so I tried to let it do it's thing and update it for me. The update downloads, then informs me that it has to restart to complete the installation. The progress bar after the restart shows it is working, and at the "Cleaning Up" stage, I am prompted with this message and only have the option to "Restart": The update "Mac OS X Update" can't be installed. The update could not be expanded, and may have been corrupted during downloading. The update will be downloaded and checked again the next time that Software Update runs.
I tried that method about 5 times, and kept getting the same thing. I read that I should try to download the .dmg files directly from Apple's site which I did. I downloaded the Combo client version and just the regular client version but when I try to open both .dmg files, I get "invalid checksum".
I did a disk utlity scan which came back to say that things were OK.
What can I do?
iMac (21.5-inch Mid 2011), Mac OS X (10.7.3)