Save .mat "Unable to write file"

I'm trying to write some worskpace variables with the command:

save('Z:\dir1\dir2\filename.mat','var1','var2','var3','var4','var5');

Where Z: is a windows (SMB) network drive. I get the following error when I try the command:

Error using save
Unable to write file
'Z:\dir1\dir2\filename.mat'

I have written many .mat files before in Z: without issues. In particular 'var1' is a relatively big variable, a 2605056x91 single array. When leaving out 'var1' the writing works, and trying to write only 'var1' also fails, so it seems to be a problem related only with 'var1'. I have write permissions since writing to the same location works with smaller size variables.

I also have tried writing the same variables (including 'var1'), with the same file name, to a different (SMB) network drive and the save works correcly. So the problem is only in the Z: drive, with 'var1'. Have anyone had a similar problem, or have any idea what could be the problem?

BTW, I also tried 'fwrite' of a large size binary file (larger size than the correctly saved '.mat' in the other network drive) to the same location in Z:, and it works correcly.

If it helps, the output of the try catch "getReport" when the save throws the error message is:

Error using <a href="matlab:matlab.lang.internal.introspective.errorDocCallback('save')" 
                       style="font-weight:bold">save</a>Unable to write file'Z:\dir1\dir2\filename.mat'.

And the MException identifier is

"MATLAB:save:cantWriteFile"

Thank you.

Answer 1

[Matthew Moschella]

For the scenario when you attempt to save 'var1', have you tried changing the 'version' flag of the save function to '-v7.3'?

In your case: save('Z:\dir1\dir2\filename.mat','var1','var2','var3','var4','var5','v7.3');

[Walter Roberson]

Small correction: it would be

save('Z:\dir1\dir2\filename.mat','var1','var2','var3','var4','var5','-v7.3');

Using -v7.3 is certainly what I would try in this situation. That said,

2605056*91*8 is less than 2^31 so the variable should fit in a -v7 file even if the variable is double precision instead of single precision. (It is not immediately clear what "single array" means in this context.)

[Alan Miranda]

Yes, I also tried with the flag '-v7.3' and still the error appers. Also with the '-nocompression' the error appears. Yes I mean single precission array, so indeed it should work with the basic "save" command.

[Walter Roberson]

Is it possible that you are running out of disk space on z: ?

[Alan Miranda]

No, I do have several GB of additional space than needed