There’s a thick white line in the middle of the screen, on Safari
On my Macbook Air, there’s a thick white line in the middle of the screen, on safari, that prevents me from using the app
[Re-Titled by Moderator]
MacBook Air 13″, macOS 10.12
If you take a screenshot of it, does that white line also appear in the screenshot?
Take screenshots or screen recordings on Mac - Apple Support
If it does not, the likely cause is hardware-related, and a trip to the Genius Bar will be required. Click the Get Support link above to get started.