: It is generally safer to use the Chrome Web Store or Firefox Add-ons rather than downloading .zip files from unverified third-party sites, which may contain malware. How to Delete ALL Messages In Facebook Messenger
: Toggle the switch in the top-right corner to Developer Mode .
: Many versions include a "Choose and Delete" feature to tick specific boxes next to threads instead of clearing the entire inbox.
: Open Chrome and navigate to chrome://extensions/ .
These extensions typically inject new interface elements, such as checkboxes or "Delete All" buttons, into the standard Facebook Messenger desktop site.
If you have a .zip file of an extension (often sourced from platforms like GitHub ), follow these steps to install it manually: