Fix 'Not a valid Win32 application' error

Every so often users encounter "not a valid Win32 application" while running a program or a file with .exe extension. The error occurs in all versions of Windows operating system including Windows 10, Windows 8, Windows 7, and XP. In this post, I will elaborate what exactly Win32 applications are, what causes this error, and how to fix Not a valid Win32 application error.

What are Win32 applications?

Win32 (also referred as Windows API or WinAPI) is a standard for creating Windows applications. Besides, Win32 applications are 32-bit programs based on Win32 API standard and these applications are meant to be run on 32-bit version of Windows. Every Win32 application has .exe file extension.

Causes of Not a valid Win32 application

While starting applications, sometimes an error occurs "not a valid Win32 application error". The error indicates that .exe file has been corrupt or has not been completely downloaded. This Win32 application issue can be caused by damaged hard disk, virus or malware infection, incomplete download of .exe file, or running 64-bit application on 32-bit Windows. This problem is mostly seen in all version of Windows including Windows server 2000, the error message is shown below.

fix not a valid win32 application error

Fix Not a valid Win32 application error

The common reasons for 'Not a valid Win32 application error' are hard drive corruption, incomplete download. To fix the error, follow the below steps:

  • Check Windows version (32-bit or 64-bit) - Check if you are running 64-bit application on 32-bit version of Windows. This is one of the main reason that causes this issue since Win32 application are designed only for 32-bit version of Windows. To fix not a valid Win32 application error, check your Windows version via Right click on Computer > Properties
  • Incompatibility with installed version of Windows – There are chances that application was working fine with previous version of Windows but incompatible with newly installed Windows. To fix 'not a valid Win32 application error', right click on the software > properties > compatibility > check Run this program in compatibility mode for > choose operating system > OK.
  • Run anti-virus or anti-malware - It is more likely that virus or malware can corrupt or delete files having .exe extension. In order to fix not a valid Win32 application error, users had better run security programs such as anti-virus or anti-malware.
  • Run Check Disk and System File Checker - Corrupt hard drive or missing Windows system files can cause this error. To repair disk-related errors run Check Disk utility in command prompt. On the other hand, for corrupt/missing Windows system files run SFC (System File Checker).