App starts without all components populated or being ready to use

I've developed an extensive App in R2019b (very large number of components), and when myself or others use it in R2020a, R2020b, or R2021a, it launches to the user wih the following concerns:

• Not all of the components have been fully created
• Actions assigned during the startupFcn process have not been fully performed
• Visible components (such as an initial pull-down menu for selecting an operating mode) are not usable.

In these newer versions, a user may need to wait an additional 15-20 seconds from when the App window appears Visible to them before it truly is usable.

I've tried some other suggestions related to this issue, but without success.

• Creating the App to appear off-screen and then to move the App on-screen at the end of the startupFcn
• Pause statements to the startupFcn process
• Adding a uiwaitbardialog at the start of the startupFcn process and closing it at the end of that process
• Exporting the App file to a .m file (from 2019b version of the App)

Thoughts/ideas? Thank you in advance for any suggestions.

[Adam Danz]

All of these problems without any warnings or errors displayed?

mlapp files are often altered when opened in a different version of Matlab than the version in which they were last edited or saved. This can cause some problem but your list sounds quite hearty. Could you attach the app that was created and saved in R2019b and provide an image of what the app should look like?

[Bryan Welch]

There are no warnings/errors displayed in the App Designer or in the Matlab command window. In R2019b, it takes roughly 8 seconds to startup due to the several hundred components that are part of that App. In R2021a, I've seen it take up to 28 seconds. Those were times measured with a stopwatch, as well as with "profile viewer".

I should also state that the startup process for how the GUI initially appears is not consistent over consecutive start-up / shut-down processes, both while keeping Matlab active and after restarting Matlab. In some instances, it seems to get hung-up on the changes made during the start-up function, while other not that way in other instances.

I can't share the app given that it was developed for work, but I thought I could describe the problems I'm experiencing to get help here on the forum.

[Adam Danz]

The difference in startup speed within the same matlab session could be a result of the JIT compiler.

You might want to contact tech support although they may ask for the app, too.

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[Philipp Petr]

I am struggling with the same problem. During the startup as MLAPP, actions are possible in the UI that cause the program to crash. Can this be fixed by a splashscreen or for example by hiding the window until the end of the StartupFcn?

Answer 1

[Eric Delgado]

I had this issue... so...

(1) Open your app (all .mlap files) in the AppDesigner of this new release of Matlab, save it and then execute it. It's essential!

(2) Update your OS (new releases of Matlab crashes with old versions of Windows 10, for example).