You upgraded your Windows Virtual Machine to Windows 8 or Windows 8.1 and start facing multiple issues related to Parallels Tools:
You get the following error message:
Windows cannot access \\psf\Home\Desktop
Coherence view mode is not available and does not work
- Degraded screen resolution
- Other Parallels Tools features do not work
Parallels Tools drivers and services need to be reinstalled after Windows upgrade.
Start Parallels Desktop. Do not start your Virtual Machine or shut it down if it is running.
Open your Virtual Machine's Configuration -> General. Make sure that the type of the Virtual Machine matches the type of guest OS installed.
For example you have upgraded to Windows 8.1 Pro. The type of your Virtual Machine should be set to "Windows 8.1" as well
Note: in Parallels Desktop 8 "Windows 8" type should be used for both Windows 8 and 8.1 Guest OS.
Start your Virtual Machine, go to Start -> Control Panel > Programs and Features and remove Parallels Tools.
Once Parallels Tools are removed, reboot Windows and install Parallels Tools back.