Everyday it's something new with Magento for NO apparent reason.
Today, I tried to open my Catalog Page and there is no longer my tree or the ability to add a new subcategory. All of my items are still showing in my product Catalog, but no ability to modify or add products.
The frustration never ends . . . with Magento.
Are you referring to inside of the admin? Or the frontend? If its frontend - then I would suggest doing a full reindex..
Also when you say unable to modify.. are you trying to save them and getting some error back?
Thank you for your response!
Today -- my product tree in admin magically re-appeared.
Go figure . .