I had a couple of MacBook Pro laptops grace my desk and I have been upgrading them to Mac OS X 10.7 (Lion). The first one (maybe eighteen months old) went through without a hitch but the second one (which is a few years old) had all manner of problems including reading my original DVD-RW that I had burnt using the DMG file from the Mac App Store. Another significant problem I encountered was after the initial installation, I kept encountering the error…
“There was a problem installing Mac OS X”.
Quite non-descript and quite unhelpful and even a format and subsequent reinstall didn’t fix the problem.
What I discovered was that the setup for Lion seems to store data in the PRAM (Parameter Random Access Memory) and if this data is corrupted or becomes stale it becomes necessary to reset it in order to undertake a successful installation.
So how is it done?
- Turn off the computer,
- Hold down “Command”, “Option”, “P” and “R” on the keyboard,
- Turn on the computer,
- Keep holding down the keys until the computer restarts itself again (maybe ten or fifteen seconds at most),
- Release the keys after the computer has restarted again.
From here you should be able to proceed with the installation of Lion with no further problems.