Web content is not displayed - just white screen

[george13]

Hi, I faced an issue on High Sierra that seems to be similar to problems reported in other threads months or years ago such as White screen of death, Safari does not render pages, but it is slightly different. For some obscure reason any web content on my MacBook turned into white screen. By web content I mean:

• Websites in Safari, Chrome, Firefox
• Settings page in Chrome, and preference page in Firefox, which are HTML based
  
• Content in AppStore app - yes, I just see white page so can't install upgrades!

If the internet connection slows down I can see that the web page is loading, but after a few seconds it turns white. What's more, if I move mouse cursor over the page I see links in the status bar and can click on them, but just see white...

What I've tired so far that didn't work?

• Clear history and all web data
• Remove Cache.db from Library/Caches/com.apple.Safari/
• Reinstall Chrome and Firefox
• Create a new user account on my MBP
• No, I don't have latest backup

What the heck?!?