At the company I work for we deploy Dell Oplitplex 760 or 780 and two E1916H Dell Monitors. We use the on board DP for one and on board VGA for the other.
Before we send them out to the remote users, we test them, and see no issues, however some users experience the following error:
The current input timing is not supported by the monitor display. Please change your input timing to 1336x768@60hz or any other monitor listed timing as per the monitor specifications.
This error comes up prior to the Dell splash screen, and the users are unable to bypass it without disconnecting one of the two monitors. However when they do so, the encryption software we use errors out and they are unable to get past it. The only work around is to leave one unplugged (does not matter if it is the VGA or DP) until they get to the windows splash screen, then they can plug in the second monitor and it works fine.
We have been unable to duplicate this error prior to the machines and monitors being sent out or on any of our test machines or when their machine is brought in.