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Home / Cannot create another instance in Windows 10 ver 1703


I am having trouble running a 2nd instance of Sumatra PDF reader, when I have tabs enabled.
No matter how I start sumatra, it always goes back to the same instance that is already running.
I also tried using shift-double-click on the sumatra shortcut, since for edge web browser and other things in Windows 10 it starts a separate instance. But still no help with Sumatra.
I checked the advanced settings, and “reuse instance” is already false. In fact, setting it true has no effect.

What I am trying to do, is have 3 related PDF’s open as tabs of a single Sumatra window, and 2 others opened as 2 tabs of another Sumatra window.

I tried disabling tabs, and then I could make a separate window for every file – many instances. But that doesn’t let me group several files in a single instance, like tabs would. I only want 2 icons (1 per group) to show up on the Windows taskbar, not 5.

I tried dragging a tab out of a window to make it its own window, but that doesn’t work.
I don’t need this feature, its just another way I thought the software might prefer I act to get the same job done.

My PC is running Windows 10 Home ver 1703 build 15063.296
I installed the 64 bit version of 3.1.2 Sumatra

Perhaps someday Sumatra can be what I need.


Yes, that is currently a limitation of the tabs mode.



the work around is to open a second “window” by calling a second copy of exe
Sumatra could be coded to spawn a second instance however a simple copy.exe achieves the desired result