I have a 2014 Retina 5k iMac (with the bigger Gfx Card), currently i added a 4k Monitor as a second screens. Now the Windows 10 background image get's destroyed after some use of the VM. Normaly i give the VM 1 GB of my 4 GB Gfx Card RAM. And the problem occurs. Even with more Ram vor the Gfx Card the problem still exists. The second screens is in portrait mode left from the imac, i attached a screenshot of the mess Of course, Parallels 10 and Windows 10 are fully patched, and the current version of the Parallel Tools are installed.
Hi Albert, Please try re-installing Parallels Tools, referhttp://kb.parallels.com/4841 & check how it goes. Also try disabling DirectX, from Virtual machine configure >> Hardware tab >> Video >> Disable DirectX
Reinstalling Parallels Tools seems to helped a little bit, now the Background is mostly black then "destroyed". But sometimes also destroyed like bevor. Disabling Direct X ist not an Option, the CPU is not able to push that many pixels in any usable way. I switched that back. Hoping vor Parallels 11 which should be out in a couple of days https://en.wikipedia.org/wiki/Parallels_Desktop_for_Mac#Version_11
