Error using writecell() : Permission denied

I currently have code in FolderA which runs a function that needs to access csv files in FolderB, but I am being denied permission to edit/enter the folder and its contents, though I (should) have full admin privilages on my computer.

folder = 'C:\Users\...\FolderA\...\FolderB'  % folder I want to access containing several csv files
if ~exist(folder, 'dir')
    mkdir(folder);
end
fullFileName = fullfile(folder, 'SRM_design.csv');
titles={'A', 'B', 'C', 'D','E','F','G','H','I','J'};
M={300,1,0.05,625,14.7,12.4,0,1,15,0.97};
M=[titles;M];
fname='fullFileName';
writecell(M,fullFileName);

When I run the above within my function, I get this error:

Error using writecell (line 149)
Unable to open file 'C:\Users\...\FolderA\...\FolderB\filename.csv' for writing:

Permission denied

When I run the same function within FolderB it works fine.

I will need to access this folder several times within the code and will need access to the files edited within FolderB.

Answer 1

[Nicholas Brophy]

Checked to reconfirm function runs properly within Folder B. When it didn't work I realized that the document was open in excel and therefore locked for editing. After closing the document it worked just fine again within both folders.