I'm having some trouble with my MacBook Pro Retina display.

When it starts up, the display momentarily shows strange colours in 'blotches' on the screen (see image). This just lasts for a couple of seconds before the regular login screen shows up.

Is this likely to be a hardware or software issue? I had a warranty repair on it about 18 months ago and since then the screws on the bottom keep loosening, so I'm not sure if this is connected.

display on startup

2 Answers 2


Actually it seems to be a high Sierra but but even I have a 2015 MacBook. I get the same issue when I wake my mac from sleep. So don't worry it is not a hardware issue. If you are concerned run Apple Hardware Test by holding the D key at start-up chime without anything connected to the mac.


This is most likely a hardware issue since the weird colours appear before the login screen loads.

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