Does this happens immediately upon tapping History from the hamburger menu? If not immediately, are you able to tap the bin icon at the bottom-left of the list of sites in your History, and then tap "Today" (be conscious this will delete Firefox history from the last day)? Does that solve the problem? If not, try again, this time tapping "Today and Yesterday" (be conscious this will delete Firefox history from the last 2 days). Does that solve the problem? If it crashes immediately before you can follow the above steps, then from Settings > Data Management (under Privacy) in the hamburger menu, can you try deleting your Browsing History this way? Be conscious this will delete all of your history. If this is a concern, you can tap Web Site Data at the top of the Data Management screen and review the sites in your history (although this too might crash Firefox. This article may be of further assistance: [[Clear browsing history in Firefox for iOS]] Let us know how you go.