How to start a 64-bit process from a 32-bit process

user_129404 0
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I am trying to run a 64 bit executable (java.exe) from our 32-bit .NET application. I am using Process class and invoking cmd /c <command name> in order to support all possible commands (like dir, cd etc).

The problem is that on my machine I installed 64-bit version of JRE and java.exe is only available from C:\Windows\System32 folder (x64). I have tried explicily starting 64 bit version of cmd.exe by calling C:\Windows\System32\cmd.exe but it gets redirected to SysWOW64 due to calling process being 32 bit.

Is there anything else I can do to get this to work?

EDIT The whole cmd /c thing is a bit of a red herring. It is not part of the problem, being able to run 64 bit executables is.

syswow64 32bit-64bit process .net
7 Answers
Michael_671320
user_1847740

To run process/script via 64-bit cmd.exe you might use this:

%windir%\SysWOW64\cmd.exe /c %windir%\sysnative\cmd.exe /c ProgramToRun parameters

This solution works universally from both 32-bit and 64-bit processes.

p.s.
%windir%\sysnative exists only in 32-bit processes.
%windir%\SysWOW64 exists both in 32-bit and 64-bit processes.

user_13517400

"sysnative" seems to have some drawbacks.

Example: When you start powershell.exe via C:\Windows\sysnative\WindowsPowerShell\v1.0\powershell.exe some CmdLets like Get-AppxProvisionedPackage" and "Get-WindowsCapability don't work / throw exceptions:

Get-AppxProvisionedPackage: "Error setting current directory to "C:\Windows\SysNative\WindowsPowerShell\v1.0": Part of the path "C:\Windows\SysNative\WindowsPowerShell\v1.0" could not be found"

(translated from German "Fehler beim Festlegen des aktuellen Verzeichnisses auf "C:\Windows\SysNative\WindowsPowerShell\v1.0": Ein Teil des Pfades "C:\Windows\SysNative\WindowsPowerShell\v1.0" konnte nicht gefunden werden.")

There might be similar problems running other processes than powershell (whenever the process source directory is important?) ...

user_117543820

Here's a way inside a cmd window to switch to 64 bit cmd in the event you find yourself in the 32 bit version:

if %PROCESSOR_ARCHITECTURE%==x86 %windir%\sysnative\cmd

Or to conditionally execute in 64 bit from inside a 32 bit batch process:

if %PROCESSOR_ARCHITECTURE%==x86 "%windir%\sysnative\cmd" /c "someProgram"

Or even better:

set "commands=multiple commands & to execute"
if %PROCESSOR_ARCHITECTURE%==x86 ( "%windir%\sysnative\cmd" /c "%commands%" ) else ( %commands% )
user_32209830
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