Windows – Run Multiple Instances of Any Application

multiple instanceswindows

Suppose some author has enforced his Windows application to be single instance. Is there any way to make multiple instance of this application (aside from running inside a virtual machine or requesting the author to rewrite the app)?

If there is a readymade tool, I would like to know it. (I have tried sandboxie and Altiris SVS without luck).

If there is nothing out there, I want to program a tool/hack that will let me do this.
I am looking for pointers where to start – what will be involved, what skills would be needed. I have moderate programming skills in C and Java.

If this cannot be done, please explain why.

EDIT: I know its a bad idea but I still need to do it (for various reasons). I want a generic way that works for any application and does not introduce errors.

Best Answer

Many applications check the global list of processes (with EnumProcesses, OpenProcess, GetModuleBaseName, and similar functions) or list of windows (with EnumWindows, EnumChildWindows).

You may try to set hook (see samples SetWindowsHookEx, CallNextHookEx, etc) to hook those specific API function calls from that application and replace requested data in response with yours to fool the application.

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Windows Media Player – How to Run Multiple Instances

Need to know what OS, but I believe that you can do this by running the "background" instance through "run as different user" on XP and up. Select the music and play.

Next, double click and open whatever videos you want normally, the new instance should open up in your user. If it tries opening with the first instance then do the same - right click, do "run as different user" and choose your own.

If however this does not work, I highly recommend you look at VLC, I use it for opening multiple videos at once in order to compare them, through one setting, it has no problem in opening up as many copies as you want.

Windows – How To run Multiple Versions of the Same Program on Windows 7

For some applications you can copy the entire application to a different location and rename the executable file (App_1stCopy.exe) and then you can run multiple instances of that app.

But notice that this approach may not work, due to devices or log files or settings being used simultaneously by multiple apps.

1st instance -> run original App.exe file.
2nd instance -> run coppied App_1stCopy.exe file.
3rd instance -> run 2nd coppied App_2ndCopy.exe file.
....

Best Answer

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Windows Media Player – How to Run Multiple Instances

Windows – How To run Multiple Versions of the Same Program on Windows 7

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