How to: Run a Unit Test as a 64-bit Process
If you have a 64-bit machine, you can now run unit tests and capture code coverage information as a 64-bit process.
To run a unit test as a 64-bit process
If your code or tests were compiled as 32-bit/x86, but you now want to run them as a 64-bit process, recompile them as Any CPU, or optionally as 64-bit.
For maximum flexibility, you should compile your test projects with the Any CPU configuration. Then you can run on both 32 and 64 bit agents. There is no advantage to compiling test projects with the 64-bit configuration.
Open the Test Settings file for your tests.
In the left pane, click Hosts.
Select the Host Type that you want.
In the Run tests in 32 or 64 bit process drop-down list select Run tests in 64 bit process on 64 bit machine.
Click Apply and then click Close.