MATLAB: File not found in current directory

file not foundMATLAB

This sounds very similar to other entries in this forum and elsewhere e.g.
https://au.mathworks.com/matlabcentral/answers/353198-why-can-t-matlab-access-a-file-that-is-in-its-current-directory
https://au.mathworks.com/matlabcentral/answers/113517-m-files-cannot-run
https://stackoverflow.com/questions/7251612/why-cant-matlab-see-my-function
But a little different, and those answers don't help me. When I got this message the first time, I realised I had forgotten to copy a file across from a neighbouring folder. (I would hardlink if windows allowed that on network drives, or softlink if matlab could follow windows' softlinks… but I digress.) Even after copying the file, I still get the file not found message. Weirdly, 'edit my_function.m' works!
>> my_function
'my_function' is not found in the current folder or on
the MATLAB path, but exists in:
    H:\path\to\nearby_folder
Change the MATLAB current folder or add its folder to the MATLAB
path.
>> exist('my_function')
ans =
       0
>> which -all my_function.m
'my_function.m' not found.
>> edit my_function.m
>> ls
.                                      
..                                     
picture.png  
figure.pdf               
my_function.m                
my_script.m

Best Answer

Hello Chris,
By default, MATLAB will cache functions and files for faster finding and executing of them. Generally files newly added to folders will be found properly, but sometimes it needs to be told to rehash before it will detect the new file. That it finds the file with edit and ls likely has more to do with those commands using a different system for finding files than the execution engine.
If rehash doesn't do it for you, try rehash toolboxcache just to be sure. Restarting MATLAB is something of the nuclear option here, but should work in almost all cases.
-Cam
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