Thunderbolt Display Resolution Incorrect

I have a iMac 5k 2019, Radeon Pro Vega 48 graphics card, with a Thunderbolt Display hooked up via a certified Apple thunderbolt adapter.

Every so often, when I wake from sleep or restart, my Thunderbolt Display will not display the maximum resolution. When I enter display preferences, no other resolutions are available. This forces me to reboot the iMac, unplug the Thunderbolt monitor, and then reconnect to achieve maximum resolution on the external Thunderbolt Display.

I am running Catalina and everything is up to date. Help. This is annoying.

iMac Line (2012 and Later)

Posted on Apr 21, 2020 9:28 AM

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1 reply

sterling r

Community Specialist

Apr 22, 2020 6:21 PM in response to datron

Hi datron,

Thanks for reaching out in Apple Support Communities. I understand that occasionally after restarting or waking your Mac from sleep, the Thunderbolt Display you're using won't show the maximum resolution and no other resolutions are available in System Preferences > Displays. I can see why you'd reach out about this behavior; I'd like to help.

I'd recommend using the steps in the resources below to reset the NVRAM and SMC on your Mac, then take some time to test for the behavior:

Let me know what you find.

Best Regards.

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Thunderbolt Display Resolution Incorrect