You could try this
- Enter
about:config into the Firefox location bar
- Search for the preference named
toolkit.startup.max_resumed_crashes.
- Double-click it and change its value '-1'.
If you check this you can take a look on:
// check whether safe mode is necessary
855 int32_t maxResumedCrashes = -1;
856 rv = Preferences::GetInt(kPrefMaxResumedCrashes, &maxResumedCrashes);
857 NS_ENSURE_SUCCESS(rv, NS_OK);
858
859 int32_t recentCrashes = 0;
860 Preferences::GetInt(kPrefRecentCrashes, &recentCrashes);
861 mIsSafeModeNecessary = (recentCrashes > maxResumedCrashes && maxResumedCrashes != -1);