'Run this Step as the following account' query

Question

I need to deploy an upgrade for hundreds of machines. A clean install is preferred over a customized package. So the source setup is used without making any changes.It took a considerable amount of time to make the upgrade work.However it works only when
the option ' Run with user rights' is selected and with the admin rights provided for that particular account.It fails with the system account. I was able to eventually make it work only with the below conditions
1) Run with user rights in program properties
2) Give Admin rights to the test account
3) If i put XYZ.exe /S in the command line it fails. So i had to put the content inside a folder called X. The data source in the package properties has \\servername\PackageID\Application name. The X folder is in \\servername\PackageID\Application name\X.
The command line is X\xyz.exe.
Point 1 and Point 3 are OK. But Point 2 is impossible as it is difficult to do for hundreds of users.
I thought of using ' Run command line ' in the TS. I tried a domain account for 'run this step as the following account'. What should i put in the command line and in 'Start in' ? I am not able to proceed and getting errors. I need to replicate the scenario
in the task sequence so that i can take care of all the three points. Is this possible ?  Looking forward for the answers from the experts...thanks

Answer 1

As best practice, see if you can have the installer create a log file, if it errors out it will indicate why or look in the temp directories for one.
It might be because the installer is extracting files or trying to extract to a temp folder under a user profile which won't exist under the System account. 
When you run the installer, check to see where it may using a temp directory.