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

Hi all,

Apple may have posted a solution to this for me: Software RAID - in my case SoftRAID.

Please see the following Apple Support article:

OS X Lion: Upgrading from Mac OS X v10.6 does not work with software RAID; "An error occurred while preparing the installation. Try running this application again." appears

http://support.apple.com/kb/TS4212?viewlocale=en_US&locale=en_US

Hopefully this will work for me. Thanks.

I had major issues on my 2008 15" MBP laptop where it would freeze and run really slowly after installing Mavericks.

Tried a SMC reset, which didn't do anything noticable for me.

Tried installing Lion to rever to an OS that was older (like my laptop), but kept getting the error metioned in this thread.

Then I installed a new HD. Same problem, couldn't get past the errror mentioned in this thread.

Then finally tried a NVRAM reset which got me into the actuall isntallation process. It seems to be actually isntalling now!

I noticed an instant performance increase after the reset, even on Disk Utility. I might not have even needed a new HD.

Reset your NVRAM: http://support.apple.com/kb/ht1379

I'll post back if it doesn't end up fully installing. Maybe a NVRAM reset would have sped up Mavericks. Should I try installing Mavericks again or stick with Lion. Not sure...! Probably will play it safe for awhile.

Good luck everyone!

Since this thread seems to be gaining more speed than the other one i'm working on, i figured i'd add these images to help you all out detailing the exact problem.

--------------------------

I'm having the same issue and I wanted to provide some info specific to my mac, and some info in general to help with diganosis.

First, my specs

Secondly, I am running an aftermarket 500 GB drive.

Third, not sure if this is realated, but this screen suggests the proress will take 3 minutes, then it abruptly umps to the restart phase after about 1.5 - 2.5 minutes.

And finally, here is the seeminly unavoidable error message.

Also, other things I've tried now are
installing it from the "show package contents area",

mounting said DMG and trying to install from there.

installing a package file called "upgradeos.pkg"

no luck.

I have the exact same issue, later tonight i will try and boot from a dvd i.e I will burn the Lion install application to a dvd snd boot from this. hopefully this may get around this issue. I'll let you know. if this dosen't work then i may have to spend a few hours on teh phone to the support help line !!

all my other updates with OSX have been smooth sailing ! not this time.

Well this is the story so far. Lion installed on my Macbook Pro, no issues. However on my Imac I'm still getting the error "An error occured while preparing the instalation..." I've booted the Lion from a DVD, reintsalled snow leopard still no luck. The next option is a phaone call to the help desk !! which I was tring to avoid.

That depends on from where you get the Lion Installer. In academia or enterprise settings this needs not to be from the App Store. I had placed mine first on the desktop and got exactly the same error message as the OP had obtained. After moving it to the Applications folder, everything ran fine.

I'm doing some reserach on what this means, but i know this error log means something to somebody on here. Here is the dump of the error log.

------------

Jul 25 03:53:17 Scott Install Mac OS X Lion[2059]: Blessing / -- /Mac OS X Install Data

Jul 25 03:53:17 Scott /Applications/Install Mac OS X Lion.app/Contents/Resources/InstallAssistantTool[2065]: Blessing Mount Point:/ Folder:/Mac OS X Install Data plist:com.apple.Boot.plist

Jul 25 03:53:17 Scott /Applications/Install Mac OS X Lion.app/Contents/Resources/InstallAssistantTool[2065]: ***************************** Setting Startup Disk *****************************

Jul 25 03:53:17 Scott /Applications/Install Mac OS X Lion.app/Contents/Resources/InstallAssistantTool[2065]: ****** Path: /

Jul 25 03:53:17 Scott /Applications/Install Mac OS X Lion.app/Contents/Resources/InstallAssistantTool[2065]: ****** Boot Plist: /Mac OS X Install Data/com.apple.Boot.plist

Jul 25 03:53:17 Scott /Applications/Install Mac OS X Lion.app/Contents/Resources/InstallAssistantTool[2065]: /usr/sbin/bless -setBoot -folder /Mac OS X Install Data -bootefi /Mac OS X Install Data/boot.efi -options config="\Mac OS X Install Data\com.apple.Boot" -label Mac OS X Installer

Jul 25 03:53:21 Scott /Applications/Install Mac OS X Lion.app/Contents/Resources/InstallAssistantTool[2065]: Bless on / failed

Jul 25 03:53:21 Scott /Applications/Install Mac OS X Lion.app/Contents/Resources/InstallAssistantTool[2065]: Couldn't bless the installation disk: /

I'd consider posting your log here and see if anyone can make sense of it. Displaying the log should be one of the options in the menu bar. i had an issue with a 'bless' terminal command that 10.6.8 seemed to clear up.

Thanks, okay well here is my install log. Maybe one of you know what is going on with this.

Jul 26 17:02:39 Sheldon-Reids-MacBook-Pro Install Mac OS X Lion[6979]: MDS Error: unable to create user DBs in /var/folders/SL/SL1e+MYNHemVO1PFMzMhB++++TI/-Caches-//mds

Jul 26 17:02:39 Sheldon-Reids-MacBook-Pro Install Mac OS X Lion[6979]: MDS Error: unable to create user DBs in /var/folders/SL/SL1e+MYNHemVO1PFMzMhB++++TI/-Caches-//mds

Jul 26 17:02:39 Sheldon-Reids-MacBook-Pro Install Mac OS X Lion[6979]: MDS Error: unable to create user DBs in /var/folders/SL/SL1e+MYNHemVO1PFMzMhB++++TI/-Caches-//mds

Jul 26 17:02:39 Sheldon-Reids-MacBook-Pro Install Mac OS X Lion[6979]: MDS Error: unable to create user DBs in /var/folders/SL/SL1e+MYNHemVO1PFMzMhB++++TI/-Caches-//mds

Jul 26 17:02:39 Sheldon-Reids-MacBook-Pro Install Mac OS X Lion[6979]: MDS Error: unable to create user DBs in /var/folders/SL/SL1e+MYNHemVO1PFMzMhB++++TI/-Caches-//mds

Jul 26 17:02:39 Sheldon-Reids-MacBook-Pro Install Mac OS X Lion[6979]: MDS Error: unable to create user DBs in /var/folders/SL/SL1e+MYNHemVO1PFMzMhB++++TI/-Caches-//mds

Jul 26 17:02:39 Sheldon-Reids-MacBook-Pro Install Mac OS X Lion[6979]: MDS Error: unable to create user DBs in /var/folders/SL/SL1e+MYNHemVO1PFMzMhB++++TI/-Caches-//mds

Jul 26 17:02:39 Sheldon-Reids-MacBook-Pro Install Mac OS X Lion[6979]: MDS Error: unable to create user DBs in /var/folders/SL/SL1e+MYNHemVO1PFMzMhB++++TI/-Caches-//mds

Jul 26 17:02:39 Sheldon-Reids-MacBook-Pro Install Mac OS X Lion[6979]: MDS Error: unable to create user DBs in /var/folders/SL/SL1e+MYNHemVO1PFMzMhB++++TI/-Caches-//mds

I had the same problem here on a Macbook Air (fresh installation of Mac OS X 10.6.8; some additional apps installed). Tried a lot of proposed solutions with no success. Even the creation of a bootable USB stick failed.

What worked for me:

- Extract the image InstallESD.img from Lion_Installer.dmg

- Mount InstallESD.img

- Start "Max OS X Lion installation.app"

- The installer will pretend to download additional content from the Internet but seems to just check data on the disk

- The installation will start

Kind of emberassing for the "it just works" company.

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.

Thats right! It worked for me!!! Hold on option, command, P & R during rebooting and great solution!

Gah, "it just works" was not quite the case this time but I got it to work! I have an early 2008 Mac Pro with a RAID array and OS X 10.6.6. I downloaded Lion and got the infamously vague error message. I then tried the following in not necessarily this order:

1) First I tried zapping the PRAM by holding down command-option-P-R all at once during startup. Nothing happened. Then I remembered tip #1: For some reason, at least on my Mac, the keyboard only works during startup if plugged into the front of my mac, not if it is plugged into my monitor. This time I got two startup chimes like I'm supposed to, showing it was indeed zapped. Anyway, still didn't help.

2) Then I tried running disk utility from my installation disk and sure enough there were some problems with the disk which it fixed. Still didn't help Lion get installed.

3) I followed the nice instructions on how to burn your own Lion installation disk at: http://mashable.com/2011/07/20/lion-clean-install-guide/#20859Step-1-Download-Li on-From-the-Mac-App-Store

When I ran the install disk from the resulting installation disk I still got failure but this time it took the form of the installer freezing up during a "checking disk" message. Sigh...

4) I checked the hardware requirements but a Xeon Mac Pro is indeed Lion material.

5) On the theory that maybe the RAID array was causing problems, I used the Lion installation disk to undo the RAID (after a full backup!) and then redid it using its disk utility. Still no good. And Mail crashes now. Sigh.

6) Started looking up prices for new Macs and getting sticker shock.

7) Suddenly inspiration! The "checking disks" error caused me to remember reading something once about external firewire disks causing problems. I unplugged my WD external firewire disk drive (that I use for TimeVault backups) and tried again with my Lion installation disk. Success! 🙂

Anyway, hope my bedraggled saga will be helpful to someone.

Hi all,

I get this same error message. I have unplugged my external hard drive and reset the PRAM, but I still get the same error. Is there any official help on this? Is there any generally agreed upon solution?

My main drive is formatted using softRAID. Could that be a source of the problem? I have a 2008 Mac Pro. Thanks.

Apple's resolution did not work for me. I get the same error running the Lion install from an external FW800 disk to a Mac mini server's internal RAID volume that is running OS X server 10.6.8. I may try the DVD method next.