Mojave - OS X 10.14.4 & DisplayLink 5.1 - Mirrors - BUT NO EXTEND

[jisleyjr]

I have a Mid 2015 10.14.4 that i use for work with 5.0 drivers installed and had no issues with my DisplayLink dock at home.
But I was having issues with getting external monitors to work on a newly acquired Mid 2015 Pro, 10.14.4. 5.1 drivers didn't work, uninstalled 5.1, tried installing 5.0.1 still no luck.

I then plugged in an HDMI cable from Mac to a monitor and that worked (just the one). I went into Arrangement tab to see if other monitors (from DisplayLink) showed up. Still nothing. Then i unplugged the USB 3.0 (to DisplayLink hub, HDMI still plugged in) and plugged back in and then all of a sudden the Arrangement tab showed 3 external monitors (Hdmi, 2 hooked up to DisplayLink). Unplugging HDMI got me down to just the 2 externals. Unplugging and plugging in the USB cable will bring back the monitors like i'd expect.

I am not sure what plugging in the HDMI did, but seemed to kick something into gear and i don't plan on updating to 5.1.

[wrbluepearl]

So, this is interesting. I remembered that I'd installed Duet Display so that I could use my iPad as a second monitor last fall. For laughs, I uninstalled the Duet Display drivers *and* the DisplayLink drivers, disconnected the DisplayLink adaptor, restarted, then re-installed DisplayLink 5.1.1 drivers. Restarted again, plugged in the DisplayLink monitor, and...

Lo and behold, the DisplayLink monitor works correctly now! Not sure if this is a "just me" fix (the sequence of steps/troubleshooting only applies to my situation) or if this is something that might apply to others. Also, I haven't extensively tested it (i.e., haven't unplugged the monitor and plugged it back in, rebooted the laptop, etc.) but it appears there may be hope.

I'm using a Diamond Multimedia USB3 to DisplayPort adaptor with a DisplayLink DL-5500 chipset in it.