Jeff Bridgman Jeff Bridgman - 9 days ago 5
C# Question

Compiling as AnyCPU produces assembly with 32BIT flag set on 64-bit machine

I've created a brand new .NET 4.5 WinForm project in Visual Studio 2013 on a 64-bit machine. After compiling, I run corflags in the .exe and the 32BIT flag is set.

Version : v4.0.30319
CLR Header: 2.5
PE : PE32
CorFlags : 131075
ILONLY : 1
32BIT : 1
Signed : 0


When I take a look at Task Manager, it's also marked as a 32 bit process.

I didn't add any references that would maybe force it to run in 32-bit mode. I took a look at the project file and didn't spot anything suspicious either.

I can run
corflags /32BIT-
on the assembly and it runs just fine as a 64-bit process.

What could be causing it to compile as a 32-bit executable?

Answer

In the project Property Pages is a page called "Build" (A).

Under the "Platform Target" field (B), is the "Prefer 32bit" field (C).

You can toggle that to remove the 32bit flag from the corflags.

Prefer 32bit (Image from VS 2015)