firefoz opens with small screen

Hi!

A quick fix could be just changing the shortcut properties. If you are on Windows, you can command the icon to always force a large window. - Close Firefox entirely. - Right-click your Firefox desktop icon or taskbar icon. - Select Properties from the menu. - Look for the Shortcut tab at the top. - Find the Run: drop-down menu and change it from Normal Window to Maximized. - Click Apply and then OK.

Hope that helps!

What macOS version do you use? There is another report from macOS 26.5.1 Tahoe user that the system no longer remembers the browser windows should be launching in full screen and now even the actual window is getting smaller and smaller with restarts.

If you grab the window corners and resize as needed (video attached) do you still get the unexpected smaller window when you next start the browser?