Opening .mat files no longer works in R2013b

Hello, I recently updated my MATLAB to R2013b. A large code that worked fine in the previous version (I believe this was MATLAB 7.2) now no longer runs. The code reads data files from .mat files which are held in another folder. In matlab 2013b the error message that appears is: Unable to read MAT-file not a binary MAT-file. Try LOAD -ASCII to read as text. When I put the mat file in the folder where the code is run then it reads fine. How do I get the mat file to also be readable from the other folder? Thanks!

Answer 1

[Adam]

If it is just a folder issue then you can probably achieve it by adding the folder containing it to your path which it may already have been in your previous Matlab since upgrades do not retain path.

Otherwise you should just be able to refer to it via its full path. Unless I am totally misremembering .mat files do not need to be on your path, but if you are trying to just refer to them by filename without the full path then they do.

[colmanp]

Thanks for the very quick answer! Unfortunately it doesn't seem to be a simple path issue. For example, I did the following 1. made a simple .mat file with a couple of variables (test1.mat) 2. shifted it into another folder 3. typed load test1.mat --> Unable to read file 'test1.mat': no such file or directory. 4. added path where test1.mat is 5. load test1.mat --> Unable to read MAT-file not a binary MAT-file. Try LOAD -ASCII to read as text. (same error as I wrote above) 6. copied test1.mat into the active folder 7. load test1.mat --> reads fine. I don't know why step 5. doesn't work - do you have any other ideas?? Thanks!

[Adam]

Hmm, I'm having trouble reproducing that as a problem. There is a setting in Preferences -> General -> MAT-Files pertaining to the type of mat files you save by default, but I don't see that as giving the results you mention for a newly saved file. I tried loading and saving both v7 and v7.3 and both worked fine (I am using R2014b, but I don't remember any problems of this sort in R2013b either though I would not that from what you said above R2013b is v7.3 which is the version for which a new style of mat files was added).

When you say you "made a simple .mat file" I assume you mean you typed something like:

save( 'test1.mat' )

to create it?

[colmanp]

Hi Adam, sorry about my slow reply - I attach a screenshot of the issue.. hope this helps! Thanks so much for your help!

In case the screenshot is too small to read, here is the text:

    >> a=1;
    >> b=[2 3];
    >> save('test1.mat')
    >> %now I transfer test1.mat into the folder 'folder'
    >> clear
    >> load('test1.mat')
    Error using load
    Unable to read file 'test1.mat': no such file or directory.

    >> addpath /Users/CarrolCP/Desktop/test/folder
    >> load('test1.mat')
    Error using load
    Unable to read MAT-file
    C:\Users\CarrolCP\Desktop\test\Users\CarrolCP\Desktop\test\folder\test1.mat: not a
    binary MAT-file.
    Try LOAD -ASCII to read as text.

    >> %now I copy test1.mat back into the active folder
    >> load('test1.mat')
    >> %now it loads the variables a and b as expected

[Guillaume]

Looks like a bug, the same thing happens to me in 2013b.

Also looks like it's fixed in 2014b. As I'm not aware of mathworks fixing bugs in older versions, you're probably stuck with it.

You can always cd into the directory instead of adding it to the path.

[colmanp]

Thanks Guillaume - I will try get my hands on R2014b..

Answer 2

[Matt J]

Sounds like a path problem. Since you recently installed a new MATLAB version, it seems likely that you simply didn't modify the MATLAB path to include all your usual data folders.

[colmanp]

Thanks for the idea.. I am still having trouble - I wrote some more details in my comment to Adam above..

[Matt J]

Do not create (or work in) subfolders on your Desktop. It does not behave like other folders and is meant just for holding shortcuts.

Also, notice from the error message that load is looking in the wrong subfolder for your file (the path name has two Desktops, Users, etc... in it). I don't know how that path got created or why a version of test1.mat resides there, but you must use full path names when using addpath, i.e,

 'C:/Users/etc...'

Anyway, the problem must be coming from specific thing about your environment (and Guillaume's). I've been using R2013b for over a year now, and have been opening .mat files without any unusual difficulties.