Unable to set breakpoint

Every time I try to set a breakpoint, the red circle comes up as long as I keep 'holding' the click, but then when I 'release' the click, it goes away. I used to be able to set breakpoints normally but now I can't

[Tommy]

Is this for all files or just a particular file? If the latter, did you happen to edit the file while you were debugging it? I've had similar issues in the past, and if restarting MATLAB did not fix it, I was able to fix it by just copying my code to a new file.

[Martin Contreras Carrera]

This is happening for all files

Answer 1

[Anmol Dhiman]

Hi Martin,

This may be related to an issue with the caching. Try running the following commands, and then try debugging again:

>> restoredefaultpath
>> rehash toolboxcache

If this works, run the command below:

>> savepath

Incase the above solution didnot help , do let me know.

Thanks,

Anmol Dhiman

[Bob]

I have the exact same issue, in MATLAB 2025B. Running these two commands:

>> restoredefaultpath
>> rehash toolboxcache

Did NOT fix the problem.

[Walter Roberson]

Sometimes MATLAB fails to set breakpoints that are set in read-only files.

[Robyn]

>> rehash toolboxcache

Thank you! This command fixed the issue for me.

Answer 2

[Image Analyst]

Is the file SAVED? If it is, there will be no * next to the file name on the tab. If it is NOT saved, there will be a * next to the filename on the tab. If the file is not saved, then you will not be able to set a breakpoint. Save it and then you should be able to set a breakpoint. Test this out and you'll see I'm right.

For those who did "restoredefaultpath", typing that will (as long as this option is set) automatically save the file. When the focus leaves the editor window (at least with my settings), the file will automatically save. When you clicked in the command window to type that, focus left the editor which caused an automatic save. So then you can go back to the editor window and set a breakpoint. So it was not the function "restoredefaultpath" that fixed it, it was the automatic saving that fixed it.