can't add my present account to folder > Get Info > Sharing & Permissions on Macbook Pro I want to access MacBook Pro OS 10.11.15 files from a Windows 7.  Can read files ok but writing causes permission problem.
ERROR AT WINDOWS IS:  "You need permission to perform this action. You require permission from the computer's administrator to make changes to this file."

At MacBook, I cannot enable Read &amp; Write for my MacBook account.

I select my hard disk.
Open Get Info > Sharing &amp; Permissions.
But + button is grayed out.

So then I tried going to the folder I'm working with;
open Get Info > Sharing &amp; Perm..;
my present account is not listed;
the + is enabled so I click it;
the list shows my present account, but disabled (grayed out)

THINGS I'VE TRIED SO FAR, THAT DIDN'T WORK:
opening Windows File Explorer with "run as administrator."
At Mac > Terminal window:  set permission of root to read &amp; write (chmod a+rw *)
Set permission of target folder to read &amp; write:
cd to folder
chmod -Rf a+rw *
Turned off Mac and Windows Filewalls.
Solution:
Mac > Sys Prefs > Sharing > File Sharing > Shared Folders: select 
Users > Everyone:  changed from 'read' to 'Read &amp; Write' fixes it.

BUT, the best solution is this:
Leave 'Everyone' as 'Read only' or remove 'Everyone'.

Press [+] box and add Mac account that is same name as my current Windows account, and set it to read &amp; write.
What magic!