Post installing DLP 9.4 from Server task, Machines are reflecting the DLP status as "Drivers installation failed".
Yes. This was nighmare.
I had this issue on my machine. I found out that one hdlp*.sys file in C:\windiws\system32\drivers dir contained previous version. (right click -> details)
So I took a correct file from working machine and replaced it manually ... then it worked well and no errors.
But of course, it's not the right solution ... McAfee should do something about that.