We’re in the process of updating the documentation for Zotero 5.0. Some documentation may be outdated in the meantime. Thanks for your understanding.
How do I uninstall Zotero?
You can uninstall Zotero just like any other Firefox extension by going to the Firefox menu Tools→Add-ons→Extensions tab, selecting Zotero, and clicking “Uninstall.”
The Zotero data directory is not removed when you uninstall Zotero.