In some situations you will notice that the navigation option is missing from the site settings screen.
Modifying the global or the current navigation is not possible.
Or is it?
Yes, in fact there are two solutions.
The reason that the navigation option is missing is due to the fact that your site does not have the publishing functionality enabled.
So enabling this feature will give you back the navigation option.
Go to Site Actions->Site Settings then under “site collection adminstration” section click on “site collection features”. Now Activate the “Office Sharepoint Server Publishing Infrastructure” feature. You need to be a site collection administrator to be able to activate this feature. Now for each site you can activate feature “Office SharePoint Server Publishing”. You are done. Now you should be able to see the navigation option.
If you don’t want to enable the publishing feature you can use the quick link /_layouts/AreaNavigationSettings.aspx
Append this directly after the url for your site and you’ll be directed to the navigation modification screen.
See more quick links in this post.