Dell Monitor banding after startup, when used with my brand new Mac mini

“Dell Monitor banding after startup, when used with my brand new Mac mini: I purchased reconditioned Dell monitor for my Mac mini and I get this horrible banding on the monitor after startup and using after computer has been idle for a while. The sellers are trying to tell me it is the computer even though it worked perfectly on another monitor I borrowed. I am worried this could harm my computer. Any suggestions, […]”

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Verify Compatibility

Locate the model number of the monitor(likely on a sticker in the back of the monitor). Then, google the model number, seeing if it is compatible with your Mac’s model.

“Dell Monitor banding after startup, when used with my brand new Mac mini: Yes, I checked it before I bought it. Thanks.”

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Thank you for the follow up reply,

Troubleshooting Monitor Banding:

A. Use a Surge Protector:

Is this plugged directly into a power outlet? Use a surge protector. It you weren’t, and there was recently some power outages, then a power spur or power surge may affect operability.

B. Single-Out this Mac:

What happens when you plug this monitor into another device? Do you still get this error? If so, it’s an issue with the monitor. If not, then it’s an issue pertaining to this Mac.

C. Single-Out this User:

See if you can get this when you create a new Administrator user. If so, then it is an issue with your current user. If not, then it is an issue with the entire MacOS., in which case, you may need to reinstall the macOS (back your Mac, first)

D. Try a Different HDMI Cable:

If you are using an HDMI Cable, then try using a different one that is 4K or 8K.