What causes NS_ERROR_STORAGE_CONSTRAINT in Firefox?

Question

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?

Answer 1

I had to clear Cookies and Site Data to fix this issue in Firefox 98.x.x (64-bit)

Go to Preferences > Privacy & Security > Cookies and Site Data > Clear Data...

All other steps like deleting webappsstore.sqlite file and fixing the profile did not work for me.