In recent versions of Firefox (since 42 or 43 maybe?), I find some sites unusable due to NS_ERROR_STORAGE_CONSTRAINT errors. I currently have 43.0.4. For example, when I go to https://jsfiddle.net/, I get this:
NS_ERROR_STORAGE_CONSTRAINT:
var baseUrlOverride = localStorage.getItem("togetherjs.baseUrlOverride");
togetherjs.js (line 85)
NS_ERROR_STORAGE_CONSTRAINT:
...ing")};window.addEvent("domready",function(){var e=document.id("add_external_res...
_dist-e..._2016_1 (line 32)
NS_ERROR_STORAGE_CONSTRAINT:
...s(e.dataset.id),t.markReadItems()),t.pushMessage("setBadge",{counter:t.currentCo...
app.js (line 1)
and the site can't finish loading. This is just one example, there are many others. Pretty much any site that uses localStorage is giving these errors. I can't find any documentation that explains what this error is or how to fix it. Any ideas?
As the other answer says, your Firefox profile got corrupted. That is true, but you don't have to abandon your profile.
You have to find your profile on disk and delete webappsstore.sqlite in that profile. This will clear all your saved site storage.
To avoid this from happening in the future make sure not to mix the same profile between Nightly / Developer Edition and Stable versions of Firefox.
The patches to fix this issue just landed and should be available soon.
Bugzilla Bug url: https://bugzilla.mozilla.org/show_bug.cgi?id=1240238