App Designer not Saving New Codes

Hello Everyone,

My app designer is not saving new codes....It shows the * sign and when I save, it does not save the new code. I then have to shut down sometimes and the code still remains like the old code without the new code...Please advise me on what to do.

Cheers

[Walter Roberson]

Does that include when you ask to "Save as" ?

At the risk of sounding obvious: is your disk full?

[DARLINGTON ETAJE]

Thanks for your response Walter. This is a new laptop.

To find it, just type 15458969 on the search bar at www.bestbuy.ca

I really don't understand. So every other thing is fast. But when it comes to saving a new code, it does not work.

[DARLINGTON ETAJE]

It's now functioning perfectly. Thank You.

MATLAB is truly an excellent platform. I am grateful.

[Walter Roberson]

How did you solve the problem?

[DARLINGTON ETAJE]

I did nothing actually...it just started working again. Maybe because the laptop is so new...that might have been the problem. But now, it functions fine again. This laptop is really fast so I was surprised with that problem. Now, within 10 seconds, the new code is saved.

[DARLINGTON ETAJE]

Actually the problem has started again. This time it doesn't save at all. I dont know what to do. Saving on the main MATLAB script is instant but on the app designer, it does not happen at all. I can't even do anything any longer.

[DARLINGTON ETAJE]

So I noticed earlier versions like R2019b is great. The one with the issue is R2021. Maybe we should take a deeper look at it

[DARLINGTON ETAJE]

But I prefer the R2021 so how do we solve this problem...Walter, please is there someone I can talk to for help with this...

[Walter Roberson]

You will probably need to create a support case for this.

I myself almost never use App Designer at all, and I only use matlab on Windows to check compatibility, not to do development.... so I do not have the experience to make any suggestions.

[Jacek Jagosz]

The problem appeared for me, on R2022b. I open an app made with R2020b, after I open it says the code got converted from R2020b to R2022b, but I checked and the code is exactly the same.

When I change any line of code, or app desription and press save, it will never get saved. I can use the app designer just fine, but the * symbol will never disappear, and the changes will never get saved. Doing save as and trying to overwrite the app file will lead to app designer crashing. Even saving in directory above also causes it to crash

But I can export the app to .m just fine, and save it to the app folder. And I can save the app (save as) will work just fine when I save to desktop. So I can workaround it, by saving elsewhere and then moving the file, but it is annoying.

I am on Linux, BTW, I checked all file permissions are correct, and the file system is EXT4. The app folder is a GIT repository, but I can't save a directory above either, where it isn't a GIT repository.

[Walter Roberson]

@Jacek Jagosz

I notice you are using Linux. I wonder if you happen to be one of the people being affected by... challenges... with the tmp directory in new linux kernels? See https://www.mathworks.com/matlabcentral/answers/1798895-invalid-cross-device-link-18-when-saving-a-file-on-arch-linux#comment_2397775

In particular, regular .m code does not need to be written to a temporary file (the existing file is renamed .asv and then the new one is written.) But .mlx files are really zipped directories of xml, so saving a mlx file could potentially involve creating a temporary directory to write XML files into and then to zip up to form the mlx file. If that (at this point hypothetical) flow is what happens, then problems with writing to /tmp could interfere with saving mlx files.

[Jacek Jagosz]

@Walter Roberson Thank you a ton for your reply! Unfortunately my problem actually seems to be different.

People who reported this issue were either using BTRFS file system or new kernel, and rolling back to older kernel fixed it. I am not using BTRFS, just standard EXT4. I also went back from Kernel 6.0 to 5.15, and the issue is the same. I also never got a single error message, like they did. That is what makes me thing this is a separate issue.

Edit: But the workaround with moving the TEMPDIR to somewhere else worked! So thank you for linking it for me. I know R2020b works just fine on my system, but R2022b is broken in this way. Hope Mathworks can figure out a way to fix their support for /tmp and tmpfs

[Adam]

I'm also having this same problem, for the 2nd time (in R2022b). I've only created two apps using App Designer in the last few years and both suffered from the same problem that they simply would not save (doesn't matter if I use Save or Save As).

First time I ended up having to re-create my App and saving worked that time, but it's frustrating after doing a bunch of work creating an app, that something as basic as Save simply doesn't work. I also submitted a ticket last time, but since I managed to work around it nothing really became of that.

Answer 1

[Shanmukha Voggu]

Hi DARLINGTON ETAJE,

We are investigating the sources for the cause of not saving new code and even some times the save may be delayed especially for large files

The reasons may be

- If the app is large then tab completion in large files can delay the save

- Parsing the contents of the file to fill in App Designer's Code Browser

The team is investigating other sources as it appears there are more causes for this than just the two above and may be fixed in future releases

I recommend splitting out some logic from the main MLAPP into external M-files to reduce the size of the app.

[DARLINGTON ETAJE]

Thanks Shanmukha for your response. The app file itself is not large even though there are over 4000 lines of code. The simulation when it runs is large hence I bought a new laptop. Now am having to code on my old laptop where I have R2019b and then when am done, I will transfer the file to my new laptop and run the simulation with R2021.

To asnwer Walter's comments...I still prefer to use MATLAB for mathematical apps. I wonder how people create all those mathematical tricks on other platforms from scratch. For serious difficult simulation, MATLAB is still the best.

[Thilina Gunawardhana]

Hi Shanmukha,

I can confirm this happening to me too. I wanted to edit an app whihc one of ex-colleagues had written using Matlab 2019b or earlier. I used 2021a because that's the latest version on my computer. App Designer was taking forever to save and wouldn't save even after 30 minutes.

However, I have installed the prerelease version of 2021b. Things have got a bit better. It saves, after taking a couple of minutes though, like 5 minutes.

Would like to see this improved in the full release of 2021b.

Thank you!

[DARLINGTON ETAJE]

Thanks Shanmukha...I look forward to using the 2021Rb App Designer on MATLAB.

[Walter Roberson]

@DARLINGTON ETAJE

R2021b is now released.

[DARLINGTON ETAJE]

Thanks for letting me know Walter...I will get it today God willing.

I appreciate you.

[Roberto Echeverria]

Hello all,

I'm using 2021b, my app designer started to behave like this just today without any previous sign...

When i clic on save / save as it does nothing.

I clic on RUN, it tries to save and gets stuck doing nothing.

I clic exit, and if try to save it gets stuck.

Any update on this?

regards

[DARLINGTON ETAJE]

Hello @Roberto Echeverria.

This problem has been solved for me especially when using R2021b. One method I used before it was solved was to save the app on a USB file and then run the app that way.

But contact Mathwork support and they will help you excellently.

[Fredrik Qwarfort]

We have the same problem, running Matlab 2022b in both Red hat 9 or Alma9. I create an empty app with just a button, and press save. But it doesn't save anything. It still shows app1.mlapp* (where the star means not saved).

But i do notice that on the file system a temporary file with size 0 is created, but nothing more. This might be a hint of what goes wrong.

We are running in a server with many users, and the file system is a mounted NAS somewhere... We don't have a local disk at all.

But in 2023b it works! But in 2023b we can't get the keyboard to work which is even worse. ~ and ^ does not show up. Is there a fix for that instead? Right now no version works in Red hat 9 or alma9...

[Gavin]

This issue was fixed in 2023b but is broken again in 2024b

When I do a save as ( e.g. to change version number) an error pops up claiming the program is open in another application (It's not). Then it trys to save and gets 10% in before hanging. App Designer has to be closed to recover.