Code Sections disappeared. Cannot use %%

I closed MATLAB and when I re-opened it, all my code sections were gone. I had previously enabled code folding around code sections as well and I can no longer do this.

For example, I have a code which has:

A=10;
B=20;
C=A+B;
D=A*B;

Previously, I could fold up the first section and run it separately from the second section. Now these code sections have disappeared. Any help or info is greatly appreciated.

I also cannot fold up my for, if, while statements etc. I have checked in Preferences and Code Folding is enabled.

[Tobe freeman]

Me, too! It's been flakey for ages. I am a little disappointed that there is nothing about this bug on Matlab central - or stackoverflow etc.

Answer 1

[Christopher Buchanan]

It sounds like MATLAB hasn't been able to parse the entire .m file - I had a similar issue until I realised one of my if/for statements hadn't been terminated with an 'end'...maybe until MATLAB is able to parse everything completely it doesn't know how to interpret context-sensitive markers like code folders and section breaks.

[Ryan Romeo]

Wow, thank you so much! I couldn't for the life of me figure out what was wrong. After reading your comment, I realized I lost my UI markers after I had initiated a for loop and hadn't yet terminated it. Didn't think that they were correlated...

[Kunxun Qian]

Made the same mistake, and thank you Chris!!!

[Ang Ji]

Thanks Chris! I terminated and it works.

[CHEN YU-AN]

Thanks, it is really helpful

[Jordi]

Note that having text after line continuations (...) may also result in MATLAB not being able to parse the entire .m file.

See e.g. https://nl.mathworks.com/matlabcentral/answers/2161765-code-folding-is-broken-can-t-see-hundreds-of-lines-of-code-in-editor#comment_3337221