How to: Debug 64-Bit Applications

You can debug a 64-bit application that is running on the local computer or on a remote computer.

If you are debugging locally, Visual Studio 2012 runs under WOW64, the 32-bit x86 emulator that allows 32-bit Windows applications to run on 64-bit Windows. Local debugging under WOW64 is supported on x64 only.

If you are debugging remotely, Visual Studio can run under WOW64 or on a 32-bit computer. You can debug both IA64 and x64 applications, in addition to 32-bit applications that are running under x64 WOW mode or on 32-bit operating systems.

To debug a 64-bit application that is running on a remote computer, you need to install the 64-bit remote debugger on the remote computer. The 64-bit remote debugger is available on the last disc of your Visual Studio installation set.

If you debug a 64-bit application on the local computer, Visual Studio uses remote debugging to connect between WOW64 and the 64-bit application on the same computer. The remote debugging components will be installed automatically when you install Visual Studio on the computer.

In either case, installing remote debugging on a 64-bit computer installs both the 32-bit and the 64-bit versions of the Remote Debugging Monitor. To debug a 64-bit application, you must use the correct version, which is Remote Debugger (x64) on the Start menu. For information about how to install 64-bit remote debugging components, see How to: Set Up Remote Debugging.

Debugging 64-bit code is almost identical to debugging 32-bit code. One difference is that Edit and Continue is not available for 64-bit code.

Mixed-mode debugging (calls from native code to managed code, or vice versa) is supported for x64 processes, if the managed code uses Microsoft .NET Framework version 4 or later.

Mixed-mode debugging is not supported for IA64 processes or for x64 processes that use .NET Framework versions earlier than 4.0.