Blank display on login screen after upgrade to Tahoe 26.2

[simona]

I have the same issue M4 Pro, DisplayLinkMgr 15.0.0 after upgrade to Tahoe 26.2 I have to headless login then connection is detected.
Support file sent

[Szymon]

Hi simona,

I suspect you have enabled FileVault during an upgrade to Tahoe 26.
Check your macOS Settings -> Privacy & Security -> FileVault. If you intend to use external screen before login, this functionality must remain disabled.

PS. I've moved your message to a dedicated thread as it appears to be a unique problem.

Regards,
Szymon

[Brant]

I also have this issue, where my screens are black at start up. I've had to unplug one HDMI from the hub, and plug it into the M4 HDMI to get it to bring up one screen. BUt when I plug it back into the hub, it flicks back to working as it should. I don't want to have to do this every time I boot up.
Is there another way? Because I'd rather not turn fire vault off, and I also don't want to wear out the HDMI port on my brand new M4.
Thanks!
B.

[Szymon]

Hi Brant,

What if you unplug HDMI from the dock and replug it into the same port immediately, skipping the intermediate step where you connected the monitor to your M4?
What is the brand and model of your HDMI monitor as well brand and model of the docking station?

Regards,
Szymon