Take the 2-minute tour ×

Here's my question. What is the best way to determine what bit architecture your app is running on?

What I am looking to do: On a 64 bit server I want my app to read 64 bit datasources (stored in reg key Software\Wow6432Node\ODBC\ODBC.INI\ODBC Data Sources) and if its 32 bit I want to read 32 bit datasources, (i.e. Read from Software\ODBC\ODBC.INI\ODBC Data Sources).

I might be missing the point, but I don't want to care what mode my app is running in. I simply want to know if the OS is 32 or 64 bit.

[System.Environment.OSVersion.Platform doesn't seem to be cutting it for me. Its returning Win32NT on my local xp machine and on a win2k8 64 bit server (even when all my projects are set to target 'any cpu')]

share|improve this question
Duplicate of stackoverflow.com/questions/266082/… –  Lawrence Johnston May 19 '10 at 16:28
add comment

5 Answers

up vote 1 down vote accepted

How to detect Windows 64 bit platform with .net? might be helpful.

share|improve this answer
I used this thanks. Thanks everyone else for their help also. –  user48408 May 20 '10 at 15:18
add comment

Try the property Environment.Is64BitOperatingSystem. This is a new one added in .Net 4.0 specifically for the purpose of checking the type of the operating system.

share|improve this answer
Thanks but I should have mentioned I'm restricted to .net 2.0 –  user48408 May 19 '10 at 15:39
add comment

Simple, safe, framework version agnostic solution without going to the registry:

    "Is 64-bit? {0}",
        System.Runtime.InteropServices.Marshal.SizeOf(typeof(IntPtr)) == sizeof(Int64)
            ? "Yes" 
            : "No"
share|improve this answer
Pretty elegant! –  code4life May 19 '10 at 17:25
Yes but if its running in 32 bit mode on a 64 bit machine the above would return false no? –  user48408 May 20 '10 at 14:19
add comment

You shouldn't even worry about this, normally. The system automatically redirects registry queries to Software\Wow6432Node when running a 32-bit app on a 64-bit platform.

share|improve this answer
To make your app run as 32-bit regardless of the platform, change the exe platform to "x86 only". It will still run on x64 platforms and be automatically redirected to the Wow6432Node keys. –  Stephen Cleary May 19 '10 at 15:22
add comment

You should not read Wow6432Node directly. Use RegistryView to specify a 32-bit view when running as a 64-bit app.

share|improve this answer
Unfortunately RegistryView available only from .NET 4.0. –  Regent May 19 '10 at 15:33
add comment

Your Answer


