At one of my current customers, I have been stuck for two days now, that one or two randomly selected applications where failing If we looked in the ‘Status Messages’ and dig al little deeper , we saw in there that :
‘Another installation is already in progress.Complete that installation before proceeding with this install.’
Knowing this is a highly secured environment , my first guess would be policies. However I overruled this thinking strategy because during the OSD process , GPO’s aren’t applied …—> That is a fact , except for one scenario I already blogged about it as described here ‘http://scug.be/sccm/2013/02/13/configmgr-2012-rtmsp1-applications-failed-to-install-during-osd-with-error-code-16389-and-denied-logon-for-domain-users-policy/’ , but that was not the issue…
Back to the drawing board and digging deeper in the smstslog file … Suddenly when hitting the F8 button a popup arrived that I needed a reboot to complete the “Kaspersky Antimalware Client” … WTF is that doing in my task sequence.
Apparently someone at the customer decided to set a policy at the Kaspersky management server , to Push / Install a Kaspersky client when he detects and scans the network for computers that did not had a Kaspersky mgmt. agent installed. That little process hijacked my Task sequence installation process and jumped in the middle to install that Kaspersky agent .
Case Closed …My advise – before troubleshooting Configmgr , just start asking questions who did changes on other parts of the environment 
Hope it Helps ,
Kenny Buntinx
Enterprise Client Management MVP