MacBook Pro (16-inch, 2019) random reboots when using Belkin Thunderbolt 3 Dock Pro

If the issue only occurs when a specific device is connected, then it usually means that device (or its cable) is at fault. Or it may mean there is a compatibility issue between two of the devices. Maybe your monitor is not compatible with the Belkin dock or with the other display. Are you connecting both displays to the Belkin dock (is this even supported)? I know with the older Macs that only one display could be connected to a particular Thunderbolt port and the display had to be the last item in the Thunderbolt chain. I don't know if this is an issue with the newer Macs with Thunderbolt 3 ports. Make sure to disconnect all other devices from both the dock and the laptop just in case there is a compatibility issue somewhere with other devices.

What happens if you connect the monitor directly to the laptop instead of using the Belkin dock? Make sure to disconnect the Belkin dock when testing the display if you still have crashes when connecting the display directly to the laptop.

If other devices directly connected to the same USB-C port on the laptop is having issues as well, then your laptop is most likely the cause of the problem.

You should try using each of the four USB-C ports on the laptop in case any of the USB-C ports may be bad. You may also want to try rotating the USB-C connector on the cable 180 degrees upside down in case the laptop's USB-C port(s) are half bad.

Which side of the laptop are you connecting the Belkin dock and display? I've seen reports on these forums that the ports on the one side of the laptop may provide more throughput to devices, but I don't recall which side.

These issues can be tricky to figure out and will require some experimentation to figure out what device(s) is/are triggering the error.

Marvae24 wrote:

Are you connecting both displays to the Belkin dock (is this even supported)?

Correct! This is the selling point of this product and why I chose it. Before using this dock, I used two cables to connect the laptop at the same time, and there was no problem at that time. The dock is used to avoid the inconvenience of plugging and unplugging too many cables.

I've never used a Thunderbolt dock so I'm not aware of any specific details on them especially regarding connecting displays. I thought I would start the discussion by asking a few relevant questions to get some more details so that it would attract and help a more experienced contributor.

I would disconnect all other devices from the Belkin dock to confirm the issue occurs with just the two displays and the Belkin dock. Disconnect other devices from the laptop's other ports as well since any other connected devices can introduce issues. You want to test these two displays & dock in the most minimal hardware configuration possible.

I just decided to quickly research the Belkin Thunderbolt 3 Dock Pro. Here is the product page I accessed.

https://www.belkin.com/us/business/hubs-and-docks-for-business/docking-stations-for-business/thunderbolt-3-dock-pro/p/p-f4u097/

If this is your dock, I noticed the "compatibility" section only mentions M1 Macs. Intel Macs are not mentioned. Perhaps this is an oversight on their page since there is a question in the Q&A section about an issue with a MBPro 16" (2019) that sounds similar to your issue:

promid · 2 months ago 

My mac (MacBook Pro 16-inch, 2019) has upgraded to Big Sur. However, when I connect it to this dock, it crashes from time to time (fan turns up and the system is turned off suddenly).

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Belkin Support · 2 months ago 

Hi. Allow us to assist you further. Please reach out to us at BelkinCares@belkin.com with the link to this post for our reference.

You may also need to contact Belkin tech support.

It works well if I connected directly to laptop with USB-C or using HDMI to USB-C.

Do the displays have any other types of video connections other than HDMI? I've seen some mention on these forums that HDMI connections may cause some problems and using a different protocol may help.

For a 16-inch MacBook Pro, all four ports should be Thunderbolt ports.

While this would be my understanding as well, I have seen a few posts from a year or two ago from a couple of well respected contributors who mentioned there may be a slight difference between the capabilities of the left & right side USB-C ports. In fact some users at one time noticed the CPU and fans would speed up for no reason if the charger was connected to the one side of the laptop, but not when connected to the other side (at least on the 16" model). I don't recall the specific details and doubt I could easily find the posts to link here.