DisplayLink not working when FileVault is enabled
 

Hi

Just wondering if you can help. I have a Mac Mini connected to a DisplayLink hub. The Mac Mini is running Yosemite 10.10.5. I have two monitors connected to the DisplayLink using DVI to HDMI cables. When FileVault on the Mac is disabled the Mac and DisplayLink work fine and I don't have any problems. As soon as I enable FileVault and restart the Mac Mini the Mac Mini can no longer detect the DisplayLink and both monitors are blank. Does anyone have any idea why this happens when FileVault is enabled and is there any way to get the DisplayLink to work when FileVault is enabled? Thanks very much and hope someone can help.

Hi Zumbir,

Don't know but FileVault working fine for me on 10.11.
You could send us the debug information following the instructions in http://support.displaylink.com/knowl...to-displaylink

Cheers,
Carlo

Thanks Carlo. I'll upload the logs. I was just wondering though if anyone else has had a problem when FileVault is enabled in Yosemite which then causes the DisplayLink not to work when a Mac restarts.

Hi Carlos

Here are the logs from another Mac Mini that I have which is running El Capitan 10.11.2. It has the same issue when FileVault is enabled as the other Mac Mini that I have which is running Yosemite 10.10.5. Both external displays are blank and there is no way to log in. I then have to connect one display directly to the Mac Mini and then restart to see the login screen and then log in. As soon as I log in the second display is then detected. I can then unplug the display connected directly to the Mac Mini and connect it via the DisplayLink StarTech hub. I've also noticed a network issue with the Mac Mini after enabling FileVault where the Mac Mini cannot detect the USB Ethernet connection on the StarTech hub. This then causes the attached issue where you get asked to reset your password.

I'm using the DisplayLink 2.5 driver. Just out of interest. What are you using to test the issue? Is it a MacBook? If you are then you'll be able to circumnavigate the issue as you'll see the login screen on the screen of the MacBook. Once you log in the external monitors are then detected. You'd need to test the issue using a Mac Mini.

Hi zumbir,

Yes the key here is that's a Mac mini with no internal screen. The same would happen on a Mac Pro.
It seems that the DisplayLink screens can't be started in the pre-login phase when FileVault is enabled.
This is not consistent with the situation where a user logs in and then logs off again: in that case the DisplayLink screens remain active.
We'll have to investigate why, I suspect we'll need to ask Apple for clarification and the answer may well be that this is as intended for security reasons.

In the short term the only workaround I can propose is to use the built-in port for one screen and the other connected to DisplayLink.

Best regards,
Carlo