Which version of IE?
Did you install any new software or do any updates around the time the problem started?
Did Windows do an upgrade/update to your IE? If so, it may have reset your preferences.
I'm unaware of any updates done.
I never had the opportunity to use Windows 8 more than a couple of weeks.
In my experience, windows 10 is the worst mess I have ever used since Windows 3.1.
I am a retired Civil Engineer, I use windows 10, I.E. 11 and the usual software of the home user, MS office and some legacy simple photo editing software, Adobe Acrobat, anti-virus software, etc.
Every time Microsoft pushes an "automatic" update at least one app gets hosed; if I'm lucky I only lose my preferences.
The file system W10 uses is a freaking nightmare; after the simple, straightforward filing tree system of win 7, the unpredictability is mind-blowing.
As with every other attempt in history, designing a system that will work for every known device is a fool's errand, and has never worked for the attempt to be "all things to all devices," and failing at them all.
After 23+ years of DOS and Windows, I see Linux in my future or, if I can afford it, Apple.
To add insult to injury, MS seems determined to "upgrade" every win 7 system remaining without the users' consent. Good luck to them!