I've been using Parallels Desktop since the first betas back in 2007 and I've just have this problem start to happen to me out of the blue.
My setup is as follows:
- 2010 15'' MacBook Pro (Core i7)
- MacOS X 10.6.4
- Parallels Desktop 5.0.9370 Revision 589435 (UK English version)
- Windows 7 Ultimate
- I'm the only user on this machine and there's only one user account created on MacOS X. I've never made any changes to my MacOS X user account or Parallels Desktop setup or location.
The virtual machine was created from scratch a couple of months ago from the Windows 7 install DVD. It worked just fine for 2 month. Then one day, and for no apparent reason, when I launched my suspended virtual machine, the message in the first post of this thread poped-up. Every single time I start Parallels desktop, it now creates a new copy of my Windows 7 virtual machine.
I'm using Spongerius's fix at the moment but have to do a bit more work as even removing and re-adding my virtual machine results in Parallels Desktop renaming it with a (1) at the end. Here is what works for me:
1) When Parallels Desktop displays the Duplicate MAC addresses error, kill the Parallels Desktop process.
2) Launch Parallels Desktop itself (instead of double-clicking on the virtual machine shortcut). This will display the list of registered VMs.
3) Right click on your Windows VM and choose "Remove". When Parallels asks you whether you want to trash or keep the hard drive file, choose "Keep". Do the same for all the duplicate VMs you have.
4) Click on the arrow beside the '+' button and choose "Open" to re-add your Windows VM. Select your VM file in the file browser (should be in Documents/Parallels/ if you've got a default install of Parallels).
5) Parallels will add your VM again but will still rename it with a (1) at the end.
6) If you've enabled the 'Show Windows application folder in the dock' option in your VM settings, it will also re-add the Windows folder in the dock with the (1) at the end. Drag it out of dock to delete it.
6) Go to the VM settings (Virtual Machine menu -> Configure) and, on the General tab, rename your VM to remove the (1).
7) Close and restart Parallels Desktop then launch your VM. This will re-add the Windows folder to the dock with the correct name.
This works for me. But I now need to go through this nonsense every single time I want to open my VM after having shut down Parallels Desktop. I'd like to see a proper bug fix for this.
Thanks.