Those of you that installed the beta build may have noticed that we made WoW64 an optional feature in Server Core for R2. In the beta it was not installed by default, which caused its share of headaches due to many installers still being 32bit or using 32bit custom actions. Based on all the feedback we received from the beta, in the RC build WoW64 is now installed by default so 32bit tools and installers will work out of the box. WoW64 is still optional, so can be uninstalled if desired.
The following server roles and features have WoW64 packages so if you need 32bit support when using any of these you will need to install the server role or feature and then the WoW64 package:
Server Role / Feature
WoW64 Package Name
Input Method Editor
Subsystem for UNIX-based Applications