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


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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