HOWTO: Fix access denied after install a new extension

When you install a new extension, you might see new menu appear on Magento Admin menu, or new configuration section in Configuration Page, but when you click on the menu item or config section you only get a "Access denied" message, like below.

Here is two things you can check to solve the problem:

1. Clear session data:
Magento stores permission in session, so permission entries from new extension is not stored yet, that's why you get "access denied" message. You can just simply logout and login again, everything should work for you. If it's not then you can clear cookie or use a different browser.

2. Check your administrator role
Sometime your configuration stops you from manage your site. You can check it by go to System -> Permissions -> Roles and then choose Administrator role. Click on Role Resources tab and change Resource Access to All. This will make sure you have right to access to everywhere of your site.

If none of the above methods works for you, leave a comment and I will try to solve it for you.