U4021QW, macOS, Thunderbolt 4 stopped working

To receive assistance from Dell chat Technical support, they need to first verify the warranty status. Click the "Get Help Now" icon on the right to start a live chat session. Provide to them the private U4021QW Service Tag.

* Go back to the top of this Monitors Forum
* Open, "Read this FIRST before posting"
* Do step #3 and then retest

* Turn the U4021QW off
* Disconnect every USB peripheral device from the U4021QW
* Disconnect every cable (including power cable) from the U4021QW
* Press and hold in the U4021QW power button for 8 seconds

* Reconnect the power cable to the U4021QW
* Reconnect ONLY the provided Thunderbolt 4/USB-C active cable to the U4021QW
* Connect the other end of the provided Thunderbolt 4/USB-C active cable to the already turned on Laptop Thunderbolt/USB-C port
* Turn the U4021QW on. What happens?

Are you running macOS 15 Sequoia?

Hi everyone, a trial version of the new macOS DDPM is now available.

To obtain this pre-release software, please contact our support team using the Get Help Now feature located at the bottom right corner of this page.

Please note that access to the trial version will be granted only after signing the pre-release software terms (NDA).

You can choose to access it now by following the terms above or wait until the global version is published on the product page.