Busy forever in Matlab R2019a

Running R2019a under Windows 10, I suddenly find that various commands cause Matlab to enter the 'busy' state forever. The only recourse seems to be forcing Matlab to end via Task Manager. The problematic commands include:

saveas % for all file types except .fig

cd % when changing to a non-existent directory, e.g. mis-typing the path.

Sometimes this makes the whole computer unusable, with other programs 'not responding' for a long time. Task Manager shows disk use at 100%, but with very little disk throughput, <100kB/s.

This didn't happen a week ago on the same machine. I haven't made any changes to Matlab, but I do accept the Windows updates pushed by Microsoft.

[Adam Danz]

Moving my answer here as a comment after ruling out this possibility.

My bet is that you're dealing with this known problem: link1, link2.

Since r2017b, when you change the cd(), the 'current folder history' is updated. When paths from network locations end up on the current folder history and the network becomes unavailable, an undefined variable or function (often caused by a typo) may cause an unbearable delay in the error message to appear.

I dealt with this problem off and on for years before finally coming up with a solution that fixes it. I recently uploaded a GUI to the file exchange that addresses the problem. If this is what you're facing, please give it a try and let me know if it works for you, too.

Mathworks is aware of this issue and is working on it according to this comment.

https://www.mathworks.com/matlabcentral/fileexchange/72519-removedrivesfromhistory

Answer 1

[Larry D'Addario]

I tried using Matlab 2018a instead, since I still have it installed on the same machine. I did not encounter the reported problem. I then re-installed Matlab 2019a, allowing the installer to overwrite all the executable files. The problem no longer occurs.

It would appear that one or more files of the 2019a installation was corrupted.