Symptoms
Parallels Desktop application gives the following message when starting virtual machine:The virtual machine cannot be started because the hardware virtualization support is disabled on your Mac. Try to restart your Mac. If it doesn't help, contact the Parallels support team for assistance.
Resolution
Please, try the solution from Knowledgebase article http://support.apple.com/kb/TS2744 first.Do not proceed with solution below if you have not applied the support.apple.com/kb/TS2744 article !
If you are still unable to start Parallels Desktop virtual machine, please follow the steps:
1. Download rEFIt disk image and vmx-var-set.efi zip archive attached to this article.
2. Mount rEFIt disk image.
3. Decompress vmx.zip archive.
4. Copy rEFIt "efi" folder to root of startup volume.
5. Copy "vmx" folder into "efi" folder at root of startup volume.
6. Open Terminal from /Applications/Utilities/Terminal and issue command:
cd /efi/refit
Press Enter.
7. Issue command:
./enable.sh
Press Enter.
Enter your user account password when prompted.
10. Restart computer, holding down Option (Alt) key on keyboard until you see boot device selection menu.
11. Select rEFIt boot device to enter rEFIt menu.
12. In rEFIt menu, select Console. At console prompt, enter volume command: fs1: , after that enter command: ls
13. If root of startup volume is listed (NOTE: you should see items such as: Users, Volumes, etc, mach, private, var, usr), enter command:
cd efi\vmx
(If root of startup volume is not listed, try other volumes, for example fs0: or fs2)
14. Enter command:
vmx-var-set.efi
(If an error message was displayed, here or at any point prior to this, it is possible that some files are not in the right place, or you missed a step. Try the steps again from the start.)
If no error message was displayed, enter command:
exit
15. From rEFIt menu, boot into Mac OS X (usually the first menu item, apple logo).
16. Remove "efi" folder from root of startup volume.
17. Open Apple menu > System Preferences > Startup Disk. Select your normal Mac OS X startup disk. Close System Preferences.
18. Shut down. Leave computer completely off for 10 seconds.
19. Turn computer back on and boot up normally (no keys held down).
20. Run Parallels Desktop.
This solution has been provided by one of our customers and has been thoroughly tested by Support department.