Failed to load VMMR0.r0

[cergel]

Bofore upgrading VirtualBox to 4.1.8 I recieved this merror message;

"Failed to open a session for the virtual machine XP.
Failed to load VMMR0.r0 (VERR_SUPLIB_OWNER_NOT_ROOT).

Result Code: NS_ERROR_FAILURE (0x80004005)
Component: Console
Interface: IConsole {1968b7d3-e3bf-4ceb-99e0-cb7c913317bb}"

Nothing changed after the upgrade, gives the same error message.
Looked up for a similar issue but couldn't find a solution
Any help is appreciated

[Perryg]

Run the Repair Disk Permissions using Disk Utility on your MAC host then it should work.

[cergel]

Run the Repair Disk Permissions using Disk Utility on your MAC host then it should work.

thank you Perryg,
I tried but unfortunately did't work, still gives the same error message.
is there anything else we could try?

[Perryg]

Failed to load VMMR0.r0 (VERR_SUPLIB_OWNER_NOT_ROOT).

If you are still receiving this error the file permissions are still not correct for the folder that holds the VirtualBox program.
Are you sure that you ran the Repair Disk Permissions, and not the disk repair?

[cergel]

Are you sure that you ran the Repair Disk Permissions, and not the disk repair?

I tried Repair Disk Permissions twice and following result does not include the file holds the VirtualBox

[cergel]

in other topics there is such information;

be careful to change the permissions of / opt you can crash your system, this solution is dangerous to the OS

I tried the "Repair Disk Permissions" from the Disk Utility on host Mac HD several times but no change what so ever.
Unfortunately I have important files on VM and cannot risk a crash, don't have a clue what to do, feels like hands are tied.
someone with more information on this matter please help me out.

[cergel]

Finally after examining Virtual Box log files i saw that it complains that /Applications folder is not owned by root... a "sudo chown root /Applications" fixes the problem
It came from https://www.virtualbox.org/ticket/7889

I found the quoted solution but others are warning abaout a possible OS crash, what do you think?

[Sergiu]

Run the Repair Disk Permissions using Disk Utility on your MAC host then it should work.

thank you, this worked for me