Rated 3 out of 5 stars

After updating to FF53, FF53 will not start. I'm lucky to have some computer knowledge so I have started FF in safe mode and do some diagnostics, and found this add-on to be the problem. But for the average joe, the only thing they have is frustration and turn away from FF. I myself has switched to chrome for 1 day before i found out the cause, if I'm not a FF lover I'm afraid I will just left FF and use other browser instead. How FF can detect faulty add-on is something Mozilla needs to address.

This review is for a previous version of the add-on (1.6.3). 

This is actually a Firefox bug. StartupMaster 1.6.2 was explicitly marked incompatible with Firefox 53, but Firefox only disables (or upgrades) the addon after the first successful startup, which never happens. I've implemented a workaround, but you need to upgrade StartupMaster before you upgrade Firefox, otherwise there isn't much I can do to help you. I can't touch the old version already installed on your computer.