Steps to reproduce: 1. Install FF 25.01 2. Install Nightly 28.01 3. Make Nightly as default browser 4. Remove Nightly 5. Make FF 25.01 default browser 6. change the default firefox protocols in windows, only the nightly shows and I can not unclick it. When I attempt to click on a link in an email (Windows Live) I get "Class not registered" https://support.mozilla.org/en-US/questions/979413 http://forums.mozillazine.org/viewtopic.php?f=23&t=2630261 Actual results: -Got error message "Class is not registered" -Side affect of work around is when the newer version of firefox is uninstalled(ie Nightly) the user dated is erased. "Remove my Firefox personal data and customizations " is not selected. Expected results: -Nightly is unclickable in the option to change default browser -yoga convertible and after the last update, every time I flip to tablet mode every page reloads and as an app where possible. I would be in the middle of something, flip to tablet and lose everything I was working on.
This will be disabled in bug 940677. The rest of the task and this particular bug can be fixed in v2 when we re-enable the feature once it has some kind of UI that tells users a switch is happening.
A new comment and attachment was posted to a related bug, Bug 870312 - Installing Nightly causes "Class not registered" error on click on link in other apps after uninstall See bug 870312 comment 4 and attachment 8383392 [details] posted 2014-02-27