App Designer can't open .mlapp file
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René Lampert
on 19 Mar 2022
I have a massive propblem with a GUI in app Designer that I'm currently working on. I worked several week on this code and now I can't open the mlapp file anymore. The big problem is that I can't even open my code to debug - I have absolutely no idea what going on here. In the morning it worked fine but obviously I have an error somewhere in the code - but, as already mentioned, I can't take a look at the code.
I always get the following error:
Error using which
C:\Users\rene\Desktop\MATLAB\Kickbase Cup\KickGUI.mlapp: Can't open file.
Error in run (line 55)
pathscript = evalin('caller', strcat('which(''', script, ''')'));
I'm in desperate need of help.
Thanks
3 Comments
Image Analyst
on 19 Mar 2022
It's just a text file. Can you open it in a text editor or word processor? Does it look "normal" there? Maybe there are some weird characters somewhere in it that prevents it opening in app designer.
Accepted Answer
Image Analyst
on 20 Mar 2022
Sorry for your loss. One other thing to try, before you do anything else is to see if there is a backup file with the same name but an extension of .asv.
You can set up making backups in your Set Preferences button on the home tab of the tool ribbon. Go to the Editor/Debugger -> Backup files section.
More Answers (3)
dijil hicham
on 19 Nov 2022
Hi ,
I had the same problem. Unfortunately, I could not find a way to run the application. One solution to at least recover your source code is to create a blank project, then in the editor, click on "compare" and select your corrupted project. A window will appear with the source code.
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Chao Chao
on 18 Aug 2023
I had the same mistake just now. At first I want to try to change the suffix txt and expect to see the code. But the disappointment is that this mlapp is in binary file form.
Luckily all my code is backed up on onedrive. So I tried to restore the mlapp to the previous version a few days ago and temporarily cut the offending mlapp to the previous folder.
It is ridiculous that the restored version is still not usable! So I re-cut the problematic mlapp from the previous layer folder back to the original folder, and it actually worked again.
I can't figure out how. I have to say this is Schrodinger's mlapp
Stanislas
on 12 Sep 2025 at 8:35
There is a way to rescue your project.
I guess the issue you are facing is that you tried to set the path of your interface at its beginning, using
path('C:\your_folder')
The problem is that you replaced Matlb's path with yours. When you open the app, it tries calling basic functions that it cannot find anymore.
The solution to open the app in order to modify this mistake, is to write a temporary empty path function:
function path()
end
Place this function, named path.m, in the same folder as your mlapp project. Now you should be able to open it. You can then use the function addpath to add your folders to the current path. You can also delete the path.m function you just created.
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