An error occurred while switching to Coherence

Symptoms

• Cannot switch to Coherence mode
• There is an an exclamation mark in Device Manager in front of Parallels Display Adapter: Windows has stopped this device because it has reported the problem (code 43).

Logs

[G] 07-17 14:28:42.711 W DYNRES_GUEST /prl_tools:1484:660/ Error retrieve information about guest displays
[G] 07-17 14:28:42.711 W DYNRES_GUEST /prl_tools:1484:660/ Error occuried while set up guest display configuration
[G] 07-17 14:28:42.711 W DYNRES_GUEST /prl_tools:1484:660/ ===== DynRes transaction info =====
[G] 07-17 14:28:43.281 W DYNRES_GUEST /prl_tools:1484:660/   desired display configuration:
[G] 07-17 14:28:43.298 W DYNRES_GUEST /prl_tools:1484:660/     rect 0: head=0; [0;0] w=1280;h=778
[G] 07-17 14:28:43.298 W DYNRES_GUEST /prl_tools:1484:660/   guest displays list[full]
[G] 07-17 14:28:43.299 W DYNRES_GUEST /prl_tools:1484:660/     display \\.\DISPLAY1 (StateFlags=0x08000005)
[G] 07-17 14:28:43.299 W DYNRES_GUEST /prl_tools:1484:660/      deviceId=ROOT\BasicDisplay
[G] 07-17 14:28:43.299 W DYNRES_GUEST /prl_tools:1484:660/      DeviceKey=\REGISTRY\MACHINE\SYSTEM\ControlSet001\Services\BasicDisplay

Cause

Parallels Display Adapter is not installed properly.

Resolution

In order to resolve the issue, please do the following:

Note: Please take a snapshot of the virtual machine before performing the instructions: in the menu bar go to Actions (Virtual machine in Parallels Desktop 9 and earlier) > Take a snapshot.

Please do not forget to remove the snapshot afterwards: Manage snapshot > choose the latest one and click Delete.

Reinstall video adapter:

1. Go to Start menu in Windows and execute teh following command:

   devmgmt.msc

2. In Device Manager go to Displays > right-click on 'Parallels Display Adapter' and choose 'uninstall', also put a tick to uninstall it from Windows.
3. Wait till the resolution changes and reboot the virtual machine.
4. Repeat the 1st step again.
5. Right-click on Standard Video Adapter in Adapters list and choose 'Update driver software..'
6. Choose 'Browse my computer for driver software', specify path 'C:\Program Files (x86)\Parallels\Parallels Tools\Drivers', click Next
7. Reboot the virtual machine after installation finishes and try to switch Coherence.

Also if Coherence mode still does not work and there is an exclamation mark in front of Parallels Display Adapter in Device Manager, please contact Microsoft Technical Support or reinstall Windows OS.