Using a 32-bit dll on a 64-bit machine

Question

I have an old project that uses a 32 bit dll. This works fine on a 32-bit processor, however, when I install the same project on a 64-bit OS, it does not work.

Is there a way to convert a 32bit dll to 64bit? Is there an alternative solution to solve my 32-bit DLL in a 64-bit OS?

Answer 1

Your 32-bit dll should work fine on a 64-bit machine while it is loading into a 32-bit process - an attempt to load a 32-bit dll into a 64-bit process will fail.

If your project is .Net (e.g. C #), then you can target your build to x86 to get a 32-bit working dll correlation:

• Right click on your project in Visual Studio and select "Properties"
• On the Project Project Properties tab, make sure that the platform dropdown reads “x86” instead of “Any processor”

If the target platform is “Any processor”, then your project will usually target any platform, for example, a 64-bit OS - this will prevent the loading of a 32-bit dll.

If your project is not a .Net assembly, then the equivalent steps required to complete the above will be different.

Alternatively, you can try to get the 64-bit version of your DLL - if this is the DLL you created, you will need to port it to 64 bits yourself. If not, then you are dependent on the original vendors providing the 64-bit version.