Windows machines do not support all of the resolutions under the sun. Sometimes, especially if you're connecting to a Windows host from a Mac, your default resolution won't be supported in Windows.
YOUR REQUESTING A RESOLUTION WINDOWS DOESN'T LIKE
For instance, many Macs are natively 1440x900. On many Windows machines, this resolution is rejected. You can add this as a custom resolution to your Windows machine, or you can choose a different resolution on the Parsec Application on the client.
YOUR SERVER PRIMARY MONITOR IS PLUGGED INTO THE DVI PORT
Parsec works directly with your GPU and video never leaves the GPU memory. Because of this, you have to use a port that is directly connected to your GPU. Parsec only captures the primary monitor (which you can set in Windows). If your primary monitor is the one plugged into the DVI port, Parsec won't be able to capture the screen/change the resolution. Please switch your primary monitor to the HDMI port.
YOUR SERVER IS A HEADLESS MACHINE
Windows machines that aren't running Server 2012 or 2016 require a monitor to be plugged in. You can mimic a monitor for a headless server using an HDMI dongle, like this one. Remember, you may also need to mimic a mouse for your headless server.
CLOUD SERVERS
If you're installing Parsec on a Tesla M60, the February 2017 driver is confirmed to work with the older CUDA 8 drivers.