Reinstall Firefox is the short answer.(don't forget to save your bookmarks).
If you have noticed any updates happening to firefox over the past few days or if you had to install any plugins, try disabling the plugins.
What is ransomware and how do I protect my PC from WannaCry?
What I learned from my mentor, Oscar-winning VFX supervisor Phil Tippett
Siri vs Google Assistant
Synology invites you to visit them at Insomnia on 26th – 29th August. Book your tickets now and visit Synology.