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MarkMac9 Author

Level 1

4 points

Vertical coloured lines on the monitor

Can I start to the iMac with an external monitor? Note that I cannot see anything on the monitor other that the lines.

iMac 27″, macOS 10.13

Posted on Jun 9, 2023 3:57 PM

Top-ranking reply

rkaufmann87

Level 10

143,320 points

Posted on Jun 9, 2023 4:41 PM

This sounds like a failed GPU, while you may be able to use an external display if the GPU is failed as I believe it is then you will have the same issue with the external display. My recommendation is to take the computer to your local Apple Authorized Service Provider to have it professionally diagnosed and then you can explore your options. If you don't know of any AASP's in your area please click the following link to begin locating one.

Apple Authorized Service Provider Locator (AASP) & Genius Appointment

Good luck!

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Vertical coloured lines on the monitor

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