CorFlags.exe (CorFlags Conversion Tool)

The CorFlags Conversion tool allows you to configure the CorFlags section of the header of a portable executable image.

This tool is automatically installed with Visual Studio. To run the tool, use Visual Studio Developer Command Prompt or Visual Studio Developer PowerShell.

At the command prompt, type the following:


CorFlags.exe assembly [options]  


Required parameter Description
assembly The name of the assembly for which to configure the CorFlags.
Option Description
-32BIT[REQ]+ Sets the 32BITREQUIRED flag.
-32BIT[REQ]- Clears the 32BITREQUIRED flag.
-32BITPREF+ Sets the 32BITPREFERRED flag. The app runs as a 32-bit process even on 64-bit platforms. Set this flag only on EXE files. If the flag is set on a DLL, the DLL fails to load in 64-bit processes, and a BadImageFormatException exception is thrown. An EXE file with this flag can be loaded into a 64-bit process.

New in the .NET Framework 4.5.
-32BITPREF- Clears the 32BITPREFERRED flag.

New in the .NET Framework 4.5.
-? Displays command syntax and options for the tool.
-Force Forces an update even if the assembly is strong-named. Important: If you update a strong-named assembly, you must sign it again before executing its code.
-help Displays command syntax and options for the tool.
-ILONLY+ Sets the ILONLY flag.
-ILONLY- Clears the ILONLY flag.
-nologo Suppresses the Microsoft startup banner display.
-RevertCLRHeader Reverts the CLR header version to 2.0.
-UpgradeCLRHeader Upgrades the CLR header version to 2.5. Note: Assemblies must have a CLR header version of 2.5 or greater to run natively.


If no options are specified, the CorFlags Conversion tool displays the flags for the specified assembly.

For more information, see section II. Runtime flags of the ECMA-335 specification. For information about the PE flag, see Optional Header (Image Only).

See also