I'm presently working on the pset3 sort and search functions and I've found that the debugger button is missing from the menu bar, the viewer is still on the right, but my ability to place breakpoints is gone. Any body know how to correct the issue?

Screenshot of the IDE

  • Which browser are you using? For me it worked when I opened in another browser or refresh the browser cashe by ctrl + F5.
    – Wafeeq
    Commented Jul 25, 2016 at 11:17
  • I've got the same issue on Chrome, IE11 and Edge. Really odd, it had been working fine, but all gone now. Commented Jul 25, 2016 at 11:44
  • I have also the same issue today again. I guess Server has Problem. I even cannot got to community from help.
    – Wafeeq
    Commented Jul 25, 2016 at 12:28
  • I have the same probable too. (in safari) Commented Jul 25, 2016 at 16:08
  • I have the same problem too in Chrome and Firefox. It used to be there but now it's gone!
    – Leanne
    Commented Aug 4, 2016 at 14:40

5 Answers 5


EDIT September '16 The latest version of the IDE (69-ish) has a new utility called debug50.

I can't find a way to get the button back, but you can run the GUI debugger this way:

In View uncheck Less Comfortable. That will give more options in menu bar, specifically a Run tab and the green "> Run" button. When I tried the green Run, it did in fact invoke the debugger. You may need to experiment with "Run Configurations" (also in the Run dropdown), or the options in the "Run" window:

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  • This worked for me! Commented Jul 25, 2016 at 16:17
  • Thanks, I can get to the same point but I can see how to insert breakpoints to be able to diagnose the issues that I have. Commented Jul 25, 2016 at 16:33
  • In the source code tab/window click to the left of the line number, should place a red dot, which is the breakpoint. Commented Jul 25, 2016 at 16:51
  • None of the earlier solutions worked for me but debug50 did work.
    – Hai Shang
    Commented Oct 24, 2016 at 2:50

I've just found that if you right click on the tab for the program, the menu list includes an option 'Run this program', this opens a new terminal and runs the program using the debugger.

  • The other solution didn't work for me, but this one did, thanks.
    – roncook
    Commented Sep 1, 2016 at 18:32
  • That's so weird. I just noticed i don't even have a Run-menutab anymore. I've always been running with 'less comfortable'-view ticked off. Anyway, was able to access debugger by right-clicking on the file-tab. Thanks @Mike McClory
    – Mike224
    Commented Sep 2, 2016 at 12:14
  • I was able to get the Run bar to come up at the bottom, but when I click on runner there's no option for C GDB Debugging
    – tamj0rd2
    Commented Sep 18, 2016 at 9:17

It also looks like you can use F5 to access the debugger from less comfortable view

  • Hi, not managed to get F5 to do anything. DinoCoderSaurus' workaround is working fine for me now that I've got used to using the debugger itself! Commented Aug 12, 2016 at 8:59

I had this similar problem. Try to inspect the resource code of the webpage, look for "runbtn". You will see style = "display: none"; Delete the "display:none" and you'll see the green button. Hope it will help you. At least works for me.


If you taking CS50x through eDX then please check out the "what's new" document. There they have mentioned about a new command called debug50. It has also been described there how to use it.

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