I want to replace the default Windows 10 calculator with CalcTape.exe in the registry. How?

Question

I want to replace the default Windows 10 calculator with CalcTape.exe in the registry. How and where would I find this in the Windows 10 registry editor? :-)

Answer 1

One method that isn't too invasive and can easily be undone is to use the Image File Execution Options Debugger key. This is the same method employed by Process Explorer when you replace Task Manager.

If you typically run calc or calc.exe to launch the Calculator this will work:

1. Launch Regedit
2. Navigate to : HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options
3. Create a new reg key called calc.exe under HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options.
4. Create a new string value called Debugger.
5. The data value can then be the path to your custom exe.

A reg file export of such an update would look like the following if this is simpler to follow:

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image
File Execution Options\Calc.exe]     
"Debugger"="C:\\temp\\test.exe"

This will work for the above scenario but then there are a number of ways to launch an application and this will not cover all of them.

Answer 2

The top answer will change the app that's launched with the calc command, but the calculator key may still need further configuration:

To change the app that's launched when you press the calculator key, change the following registry value:

Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\AppKey\18

Set ShellExecute to the path you want, for example: C:\Program Files\CalcTape.exe.

Alternatively, you can set up a macro: AutoHotkey: how to assign a command to the "Calc" key?

Answer 3

I did it by renaming calc.exe to ms calc.exe Then I copied my chosing calculator moffFreeCalc.exe as calc.exe and copied that to windows\system32

Had to take ownership of the ms calc file first, before beimg able to rename it.