Only 2 of 4 Monitors Working

Hi, I have a Lenovo Flex 5 15ITLO5 with 4 27" MSI monitors. I am unable to get all 4 to display via the usb-c port. I have installed the recommended displaylink driver and most recent Windows update. I do believe the issue is the laptop does not have usb-c Alt mode. Is there a work around for this? I have tried with another laptop and works and all 4 work. Thanks, Mike

Try unplugging the power to the dock, wait 15 seconds, then back in.

Hi Michael,

Thanks for reaching out to Plugable support! I’d be happy to help with that.

For the UD-3900C4 docking station HDMI ports 1 and 2 rely on the DisplayLink drivers being installed on the computer.

When it comes to HDMI ports 3 and 4, those do require the computer to support Alt Mode for extending displays, as well as MST for extending multiple displays on the same channel. Unfortunately, these are hardware requirements, and there is no work around for allowing this without the computer having hardware that allows access to the GPU through USB-C Alt Mode.

I did find the following user guide for that laptop:

Based on that information, the USB-C port is data only and does not support Alt Mode.

With this laptop configuration, we would expect everything to work except for the HDMI port 3 and 4 along with the ability of the docking station to charge the laptop.

I hope this information helps.

Richard A
Plugable Technologies

I am having the same or similar issue. I have an ASUS FX707ZM-RS74 gaming laptop. Before I downloaded your drivers the top 2 HDMI ports recognized but not the 2 bottom ports. After I downloaded your drivers and the DisplayLink Manager, the 2 bottom recognized but not the top 2. My laptop has a Thunderbolt 4 USB-C port and a regular USB-C port. When I plug into the Thunderbolt port my other USB devices do not work (i.e. mouse, keyboard) but when I plug into the regular USB-C they work (minus the monitor issue stated above).

This is definitely odd behavior as it should be supported by both of those USB-C ports, if the specifications that I’m looking at for this laptop are correct.

For this type of situation, it would be most helpful for us to see a set of log files and if you could reach out to us, the

When you have a moment to message us, could you please let us know the following details:

  • The model of your Plugable device (located on the product itself, the box, and the quick start guide)

  • If possible, a set of log files from your system, collected with the device connected. We have a tool that automates this process, which can be downloaded from: - Please do not post log files on this forum and only send them directly to our support address.

Thank you.

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