I have a weird issue troubling my Drupal site. Upon clicking 'Add Content', my Drupal website automatically redirects to a couple of custom content types that I created using the 'Add content type' feature. For some reason, all the existing core content types such as 'Basic page', 'Article', 'Book' have disappeared.
Further probing, when I click the 'Content types' link in 'Structure>Content types', all of these content types exist and are listed, however for some reason I am unable to use them.
I am not sure where I have goofed up here, so I want to ask you guys and check what's wrong.
Thanks,
Problem:
I have experienced this same problem... in fact on a current project I lost a complete day of work (I wasn't backing up my DB often enough & my fix was to restore my DB) in attempt to resolve it.
Once I found Radix's answer I realized that was definitely what I had just done (disable all of those items in the navigation menu).
Procedure/Fix:
I then took it one step further, since, in my estimation putting these links in the navigation menu must have been an error (what business do they have there??).
I went to Structure->Menus and clicked the "list links" errr link.
Next I clicked the "edit" link on the Add content sub-menu item.
In the Edit window I selected the ----Content sub-menu of the Configuration menu.
I then verified that clicking Add content from the management menu AND from the Content window brought me to the links I was expecting, and it did.
Drawback:
I found that when adding new content types you have to modify their automated menu link by finding them under the navigation menu & setting their parent menu as ------ Add content
Summary:
Moved the Add content menu to a more logical location (so I could use the navigation menu for my own purposes without losing the ability to add content), however this requires an extra step when creating custom content types.
This issue has been asked in several formats, but as it keeps rearing its head, I will respond with a detailed explanation.
When attempting to "Add content" under administration-->Content, it is quite common to find that the content type menu items become disabled (don't know why). This can easily be remedied by re-enabling the content types in the navigation menu, like this:
Go to administration-->structure-->menus-->navigation and you will see all (or some) of your content types are disabled in the menu. Just re-enable them and you are good to go!
This may also be due to problem with the database:
If two or more entries in the node_type table have the same orig_type value, some of them may not be displayed. Compare this report: Drupal: Content type in database not in the list of content types in Structure>Content types
