Folder Locked via CMD PROMT using cacls, but now unable to open (large folder 6 GB)

I locked my folder using below command:
D:\>cacls data /e /p everyone:n

And, it should be open via below command:
D:\>cacls data /e /p everyone:f

But, as my folder is large i.e. more than 6 GB so I'm getting message "Access is Denied".

Please suggest some effective measure as it contains some IMP files.

Thanks & Regards.
-Elisha V. Masih