Cannot start VM after upgrading my Mac to OS X Yosemite DP 4

Its return me error virtualization support is disabled. I was tried to repair permissions in disk util but it doesn't help.
Any ideas how it can be fixed ? Parallels Desktop 8

 

Same boat here - I reset the virtualization setting too - no effect. Reinstalled Parallels, no effect.

 

Looks as if the Parallels 8 kernel extension signatures are not regarded valid anymore for DP4.
Console error message: "ERROR: invalid signature for com.parallels.kext.hypervisor, will not load" with similar msgs for the other Parallels kernel extensions.

Apparently the modules are not listed in /System/Libraray/Extensions/AppleKextExcludeList.kext. Maybe the Parallels development team is able to suggest a workaround.

 

No issues here with DP4. With DP3 Windows 8.1 would trigger a kernel panic after a few seconds and under Windows 7, Chrome browsing freezes the VM. After DP4 upgrade, everything is working fine.

 

Solution:

Code:

sudo nvram boot-args="kext-dev-mode=1"

Reason:
Yosemite DP4 Release Notes:

 

great! works like a charm now, thanks!

 

Will try it later today. Yesterday was downgraded to DP3 from time machine

 

jansoucek, it works fine

thank you for the solution !

 

Thank you, thank you, thank you. I was going nuts with this problem.