Too many files open error when using load and save. fclose('all') doesn't solve the problem

My code looks like this

sourcedir = 'C:\exampleDirectory\';
for i = 1:N
    exampleFilename = [sourcedir, num2str(i),'.mat'];
    structMatrix = load(exampleFilename); 
    exampleMatrix = structMatrix.savedMatrix; 
     % do something on exampleMatrix
    fclose('all');
end

I have tried sticking an fclose('all') on both ends yet it inevitably runs into:

Error using load

Unable to read file 'exampleFilename'.

Too many files open.

same happens with a similar save function. I tried running it in for loop instead of parfor, the problem persists. I can restart matlab and the problem goes away for a while, only to return when the open file number hits the limit. It is likely happening from load and save functions, but I can't see the code of load and save functions, neither do they output fid for me to close specifically.

Thank you,

[Walter Roberson]

I suggest you try https://docs.microsoft.com/en-ca/sysinternals/downloads/process-explorer to monitor which files are being opened. You would then be able to tell whether it is the load() calls.

[Saumya Tiwari]

Sorry, I was going to respond to this comment and then I got distracted. I tried to check what is being opened, it was a lot of java .jar files. Not sure if that has any connection to the problem at hand. I didn't see my file names as being left open, which was what I was suspecting before.

The windows support tech asked me to disable all non- windows services to see if it helps with the problem. This error takes a few days to pop up, so it will be a while before I find out if this solved the issue.

Answer 1

[Andreas Kvalbein Fjetland]

Try usinng the clear command instead of fclose. This worked in my test here.

clear('structMatrix') 

[Saumya Tiwari]

Thank you, seems like this solved the problem. I will update if I run into this again.

Edit: Did not work. I am clearing variables after load and save calls, no good.

[Walter Roberson]

process-explorer that I mentioned would permit you to find out more about what is being opened.