TFS and a 64-bit platform

Question:
Can Team System be installed on a 64-bit platform?

Answer:
TFS can't be installed on a 64-bit platform since it requires the application-tier to be run on a 32-bit platform.
Explanation and Scenarios: Application-tier setup on a 64-bit system scenario was not tested sufficiently by Microsoft in RTM timeline (see this post). That is why this scenario is blocked in the current TFS setup and officially is unsupported (If you try to install TFS Application-tier on a 64-bit operating system with SQL Server 2005, setup does not detect the SQL Server services and blocks the installation).

Installation choices available today are:

1. Single server setup: Can be performed on a 32-bit platform only. 
2. Double server setup:
   1. Data-tier can be installed on a 64-bit system; Application-tier can be installed on a 32-bit system.
   2. Both data-tier and application-tier can be installed on 32-bit systems only.
3. Build Server can be installed on a 64-bit system.
4. TFS Proxy can be installed on a 32-bit system only.
5. Team system client (Team Explorer) can be installed on a 64-bit platform.

Note: Choice between Single server and Dual server installation should be based on expected capacity (see TFS installation guide).