Can Lync 2010 and Communicator 2007 (w/ or w/o R2) client be installed on the same machine

Question

Can both clients be installed and used at the same time ?

The purpose of using both is based needs to develop for Lync 2010 while still using Communicator 2007 in a corporate environment. Or would a developer be forced to have two different machines/VMs/boot environments ?

Answer 1

No - you can't run both side-by-side. Installing Lync will uninstall Communicator.

However, you can use a registry hack (unsupported, unfortunately) to enable your copy of Lync to run against your OCS infrastructure. This works for R2, not 100% sure about R1.

[HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Communicator]"DisableServerCheck"=dword:00000001

If you're serious about Lync development, the best solution is to build a server environment specifically for developing against.