An error occurred while preparing the installation. Try running this application again.

Try restarting your computer holding down the 'Shift' Key. This will do a "SAFE BOOT". After doing that

Lion installed with no problem. Hope this works for somebody else. got this tip from a 'Supervisor' Tech at Apple.

I'm posting because I had the same problem, and none of the fixes in this thread worked for me. I'm also guessing a few people might want to scrap Mavericks and come back to Lion, or Mountain Lion, so hopefully my 8 wasted hours helps someone else. I was running OS X Mavericks for about 2 weeks, which ***** on my mid 2010 MBP, 4GB RAM. Since Apple makes anything other than an upgrade excruciating (read: impossible), I just blew away the whole hard drive and started over. Easy, right? Let's just say I was 5 minutes from abandoning Apple for Linux permanently. Ok, end gripe.

So, for whatever reason, the issue seems to have been related to installing from DVD. I don't care enough to explore why that might be, since I found my workaround. I downloaded the installer, burned to DVD, booted from DVD, went through the "Preparing to Install" motions about 8 times. This is pretty vanilla stuff - empty hard drive, one partition, all erased / formatted with Apple's own install media. I initially stuck with the single partition - Macintosh HD. It would never hang mid way - always would get through 100% of the preparing to install phase, and then the same error.

In an attempt to eliminate causes, I figured it would be handy if I could somehow run the same install package from the hard drive instead of the DVD. Unfortunately, I had already deleted the OS, so I had to boot into the DVD. So, while in the DVD install, I ran the Disk Utility, created 2 partitions (one Macintosh HD, and one 15GB partition for OS X Lion Install). Once that was done, still in the Disk Utility, I clicked on the SuperDisk Volume on the left (the DVD installer), and then the "Restore" tab. This effectively allows to to clone one Volume to another. So if you set the source to be the DVD Install Disk, and the Destination to be your newly minted Hard Drive partition, next time you reboot you can eject the DVD and the installer will boot from the HD. This time, it worked like a charm! Again, no idea why it would keep failing while running from the DVD drive, and work from the HD.

Hope that helps someone.

Cheers.

I was trying to do a clean install, and had this error over and over, but then I found this video that worked just perfectly for me.

My computer was with a date of 2000.

Fixed it and it worked =D

https://www.youtube.com/watch?v=Cf4TzZt24-M

@ranato.gama - Thanks so much for posting that video! Solved my problem 🙂 I forgot that my computer occasionally will set its internal clock back to 2000. Does this happen to anyone else? Is there a way to fix this?

Same issue here. 2010 MacBook Pro.

Where any of you able to resolve this?

F

Lion Installer must be copied to the /Applications folder and started from there.

Download it again and try may corrupt during download just holding option click purchase then click install and besure you run the newest download so may you can trash the curren tone

Has anybody figured out a solution to upgrade? while the clean install route may work, i'm sure its not favorable for the people in this thread.

Sorry for the doulbe post, but I'd like to add I've redownloaded it twice, one of which times, the app store was my only open application and the system was under minimum load.

I'm having the exact same issue. I've tried everything and all I have is Lion sitting on my desktop. Could Apple give us an explanation for this problem?

I was able to correct this problem by resetting the PRAM and NVRAM. Took my 3 days of troubleshooting to figure it out. Also corrected some slowdown issues I was having.

Glad to hear you were able to get it installed, this fix did not work for me however.

That fix also didnt work for me. =[. Really at the end of my rope here lol.

Getbusyliving wrote:

I've tried everything and all I have is Lion sitting on my desktop.

As said, move your Lion Installer to the Applications folder and start it from there.