So looking for a solution to this one. Getting desperate. For a few days now, every time I start my MBA, I get no contents in my Mail messages (title bars normal), Safari (nothing doing, white pages; no progress bar, nothing loading; other browsers are working), and blank pages for the 5 tabs in App Store. iCloud, iTunes, and iWork (other than losing 2 docs to "can't open for a reason"; be careful people) are not affected. And iPads are working great. Recently (since Sierra I figure) when booting, MBA would sometimes crash one time, then restart right away. Maybe light at the end of the tunnel though. Booting in Safe Mode, Mail, Safari, and App Store work just fine. Hopefully someone can provide a solution. Thanks. Update: The tab App Store in iTunes also produces a blank page. Not the tabs Library and Updates.