The Short Version: I needed to re-install OS X Lion on a system after formatting the standard partition. The install process required downloading the software from Apple first but it was blocked by network authentication. Requesting a temporary lifting of network restrictions for this system provided me with enough time to complete the download.

I needed to format a MacBook Pro that came with OS X Lion (10.7). My assumption was that the process would work the same as with disc-based installs.

The usual saying about assumptions applies.

The system didn’t have any problems at the beginning. I formatted the primary partition by booting to the recovery partition. Then, I let it begin the installation process by downloading the latest version of 10.7. I thought everything was working fine.

However, after I returned I discovered that the download had failed.

Repeated attempts to resume the install immediately failed with a “the installation information is damaged or incomplete” error. This seemed odd since I knew the recovery partition was in good shape. Then I decided to check on another problem.

In this case, the system was connected to a network that requires network authentication. Now, I could use Safari to enter credentials but this method also requires installing a software component, which I couldn’t do in recovery mode. In the end I had to request a temporary exception for the system. I figured it wasn’t able to contact the Apple server to download the latest software.

This turned out to be correct, though the error message could have been more informative if it had indicated a network or communication problem instead of implying there was a problem with files on the drive itself.

Once the network block was lifted the system continued the installation process as normal.

My incorrect assumption during the process was that Lion arrived with a complete copy of the original OS installation. This was not the case or the installation process didn’t give me the option for some reason. Instead, it required a download.

This is another example of moves by Apple that simply don’t make any sense. I can’t image how much difficulty this would create if I was a person in a very rural area that had dial-up or was using satellite with a very limited bandwidth allowance.

I suspect it’s possible that someone could receive this error on a network that doesn’t require authentication. If that’s the case then I recommend checking Internet access and DNS settings.