During Lite Touch deployments, the task sequence runs ZTIDrivers.wsf, which needs to figure out what drivers are needed for the computer, based on the PnP IDs found on the computer and the available drivers on the deployment share. For every match, the driver files are copied to the computer.
It’s possible (especially with chipset drivers) for there to be multiple drivers in the same driver directory. Because we don’t really know which files are necessary for each driver, we don’t try to separate them during the driver import process. Instead, we just have multiple driver entries (one for each INF file) pointing to the same folder.
That means it’s actually possible for the same folder to be selected multiple times, once for each INF in the folder that matches a PnP ID. And each time it’s selected, it’s copied. Prior to MDT 2010 Update 1, that could mean that the same folder (maybe 100MB) gets copied several times, overwriting what was copied the previous time. That’s not terribly efficient, so we modified ZTIDrivers.wsf to not re-copy files that already exist in the destination (C:\Drivers). (Since ZTIDrivers.wsf actually uses XCOPY, all we really did was add “/d” into the command line parameters, so XCOPY is doing the real work.)
So if you’ve complained that driver injection is taking too long, this could help out. It won’t help out in all cases (especially if the deployment share is remote or especially large), just those where there are multiple drivers in a folder.