I’ve been wrestling with an issue for what seems like ages: every time I try to change the permalink structure on a particular WordPress website everything explodes and every page I try to navigate to gives me a 403 Permission Denied error.  Yikes!

Finally found the solution and luckily it was a simple fix: just add the following line to the very top of your htaccess file:

Options +ExecCGI +FollowSymLinks -Indexes -MultiViews

Success!  Now the permalink structure can be changed to whatever I want and everything continues to navigate perfectly.