Lately I wanted to try some Longhorn builds in VMware so I installed VMware 7.1 because that's the only version in which you can get aero to work...
Some time later I wanted to install a Windows 8 beta in VMware, it failed because VMware 7 is not capable of installing Windows 8. I 'upgraded' Vmware 7 to 8 so I could install Windows 8. But at that moment I was not able to use the allready installed longhorn builds, so I unistalled Vmware 8 and reinstalled Vmware 7... I think switching between two versions of vmware is alot of work , and I wonder if there isn't a way to install both vmware version on 1 system?

I hope you guys have a solution for me!

Have you tried changing the VMWare Hardware Version? Open (do not run) the virtual machine you wish to run in VMWare 8, go to the VM menu on the menu bar, go to the Configure sub-menu, then choose Change Hardware Compatibility.... It will start a wizard. Click next, then choose Workstation 6.x - 7.x (or similar) option under the drop-down menu displayed. Then click next. You should be set!

@Patrick
Does that really work for you to see the glass effect? I have build 4042 installed in VMware 8 with 6.5--7.x compatibility and could not enable Aero glass. Indeed I have proper drivers installed and followed proper steps to change files and type sbctl etc.

Also, when the VMs created by VMware Workstation 7.x are migrated to VMW 8, they have 6.5--7.x compatibility.

I allready tried that before installing VMware 8 because I did not feel like installing vmware 7 again...
It didn't work, also when I've installed 4074 in vmware 7 and open the vm in vmware 8 the glass doesn't work anymore.