How to force a second instance of a program to open?

I'm using a piece of Windows software (DS Clock) which, by default, doesn't allow a second instance to be opened. When I double click the executable, nothing happens if the software is already open.

Is there a way I can force a second instance to open up?

If the program checks that it is the only instance, this is probably not possible if the program doesn't have such an option.

You could run the first instance in Windows Sandbox, to isolate it from the second instance, but this is not an easy solution.

I assume that the problem is showing the time in multiple time zones. I would suggest in this case to use a multi-zone clock product, for which there exist many free products.

See for example this list.

Depending on the complexity and structure of the program, you might be able to do the following:

Locate the .exe file (right-click on the shortcut -> properties -> target). Duplicate the .exe file and give it a different name. Then execute that second file next to the original one. You'll need administrator priviledges to do that.

If that doesn't work, try to duplicate the whole installation directory, but still renaming the .exe file.