Rectangular shaded area appeared on MacBook Pro Screen

"I did as you suggested. Taking a screenshot the lines don’t appear in the photos app so it seems to be a software issue. What can I do to rectify this?"

-------

This is a hardware issue.

Your Screen is Failing:

So, Get this Mac Serviced...

Contact Apple, and setup a Genius Bar Appointment or see an AASP (Apple Authorized Service Provider) in your local area.

A. Contact Apple:

• Contact Us - Choose Locations
• Proceed from there as Necessary

Or...

B. Contact an AASP: 

1. Go Here: Find Locations - Apple Authorized Reseller
2. Click: Service & Support
3. Enter: your location information
4. See: if there is an AASP nearby
5. Contact: an AASP that shows up, and find out more about the services that they offer to fix the Mac

"Rectangular shaded area appeared on MacBook Pro Screen: A rectangular shaded area appeared on my MacBook Pro screen randomly. I have never dropped the computer or spilled any liquids on it. I was using it ordinarily to watch Netflix videos and then suddenly the pixelation on the display starts to freak out. Finally dark shaded area that’s rectangular appeared. I have tried to restart the computer and nothing changed."

-------

Lines on Screen From an App:

A. Add Netflix Back:

Does this always occur with Netflix? Does it occur when you restart your Mac? If so, try removing the app, seeing if this no longer occurs.

B. Take a Screenshot:

What happens when you take a screenshot? Do the rectangles still appear when you open it with the Photos app? If so, then it is a hardware issue. If not, then it is a software issue. Go here: Take a Screenshot on iPhone - Apple Support