Mozilla, the company behind Firefox, have implemented a number of security checks in their browser related to extensions. One such check is a digital certificate that all add-ons must be signed with. This certificate is like a HTTPS certificate – the thing that gives you a green padlock in your browser’s URL bar.
You’ve probably seen a HTTPS error before. This happens when a site’s certificate is invalid for one reason or another. One such reason is that the certificate has expired.
I’ve noticed that Discord for Linux takes a very, very long time to start up – sometimes in the order of hours. During this time, my laptop gets very hot. I eventually decided to look into this and found that several instances of
xdg-mime were taking up 100% CPU. Killing them caused Discord to open instantly.
Apparently this issue is present with Spotify too. This fix will work for both of them.