Setup MDT 2012 to use USMT 3
I recently upgraded our MDT 2010 Deployment share to 2012 and ran into an issue with USMT 3. We still have some scenarios where we are deploying Windows XP so USMT 3 is required. Whenever we ran a task sequence that needed the USMT 3 files we would get an error that the files could not be found. I thought this was odd since the USMT 3 CAB file was in the correct location. Or at least it was for 2010.
In MDT 2010 you just had to leave the USMT30_x86.CAB file in the DeploymentShare\Tools\X86 folder and MDT took care of the rest. With MDT 2012 you need to create a USMT3 folder in DeploymentShare\Tools\X86 and then unpack the CAB file into this folder. It will not unpack the CAB file for you anymore. Now MDT will be able to find the USMT files and continue.
Hopefully this helps out anyone else that has done an upgrade from 2010 to 2012.
Mike C's Tech Blog 
upgrade from mdt2010 to mdt2012 give me “unable to find USMT3 files” but i not deploy xp!
only upgrading operating system to win7, refresh, replace scenario, so USMT3 is not needed.
For Windows 7, USMT 4.0 is required.
all default task sequence with backup from xp machine fail with error “unable to find USMT3 files” in ZTIUserState.log.
why?
i’m forced to use mdt2012 beta2 that work fine.
Make sure that you do not have USMT3=Yes defined anywhere in your CS.ini file.
i also try to add USMT=NO in cs.ini – no luck.
other people notice the same problem.
http://blogs.technet.com/b/msdeployment/archive/2012/03/01/now-available-microsoft-deployment-toolkit-2012-rc1.aspx
http://blogs.technet.com/b/msdeployment/archive/2012/04/17/microsoft-deployment-toolkit-2012-now-available-for-download.aspx
http://social.technet.microsoft.com/Forums/nb-NO/mdt/thread/2812fa20-93be-46ad-8c68-ba1ba5de16ef