Error while rendering plone.global_sections

Whenever I uninstall my Dexterity content type product, I receive an "error while rendering plone.global_sections" at the top of my page. However, when I install the product, the error goes away.

Does anyone know why I get this error when I uninstall the product? I would have thought that errors would occur when I install a product and not uninstall a product. Any advise would be most appreciated.

you may have an instance of the content type you're removing on your site root being referenced by the global navigation.

hvelarde, that makes total sense. I have one particular page that I cannot seem to delete. I even when I went into the ZMI to do it but to no avail. I keep getting this error:
ComponentLookupError: (<InterfaceClass plone.dexterity.interfaces.IDexterityFTI>, 'manuals')

How does one delete a stubborn page in Plone?

As a general rule, fixups like those above usually need to happen before the required infrastructure has been removed. In your case, you first delete the objects for your dexterity content type before you remove the type implementation.

There is a low level way to remove broken objects even without the (usally) necessary infrastructure. However, it is error prone and requires lots of internal knowledge (to avoid inconsistencies). In the general case, you should not go this way.

Thanks dieter, that makes total sense. I created a new Plone instance instead since I am not too far along in the project. Thanks so much for your advice.