WinBox connecting via MAC address disconnects after 5 seconds. Connecting by IP works fine. This is on default router configuration and Windows10 PC connected directly to Eth2. WinBox 3.40 (newest) and RouterOS 7.13.4 (latest stable).

Similar issues here:
Unstable MAC Winbox connection
Winbox close connection in a loop
Cannot connect to hAP ac2 via WinBox using MAC address
Winbox mac-connect Windows 11 not working
Mikrotik winbox not connecting
Winbox dropping connection
Can't access RouterOS via mac address

The solutions posted in other threads I've tried so far:

• set static IP on PC
• enable Jumbo Frames 9014 in NIC properties
• disable all other network interfaces including Bluetooth/Wireless
• Tools->MAC Server is set to LAN
• update WinBox to latest version
• run WinBox as Administrator
• try WinBox64 as well as WinBox32 bit
• disable Windows built-in antivirus
• close all windows from previous sessions (in WinBox)

Edit, suggestions below and more I found elsewhere:

• set Windows network profile to private
• disable Windows firewall
• try with switch between the PC and the router

Hello there,

Have you tried to turn off all the deafult windows firewalls (i.e private and public domain) before? Also, if the router has default configuration or it is already configured with DHCP, the interfaces (consider to take a look on the other interfaces on router that you can use to access the router) that directly connected into your router should be set to obtain the IP Address automatically and then try connecting using MAC Address if is discovered, and remember after doing some windows change like turning off firewalls/antivirus to consider rebooting the windows to apply the configuration perfectly.

Perhaps, when you open the WinBox on the first time there will be pop-up message that contains network firewall permissions that you should click "Allow Access" for granting the application to run without any issue. Lastly, I've used to pick the long-term version of RouterOS that relatively more stable in technical.

Hopefully that could try helping your situation
Regards.

Windows 10 tends to treat network connections as "public" applying to it a number of firewall (not antivirus) rules,
Make certain that the network is "private" and/or try disabling firewall.
Windows 11 is a troublemaker in this, but 10 usually works, unless there is some regression bug of some kind in 7.13.4.

Just tried setting the network to private and disabling windows firewall altogether, it still disconnects.

I have been experiencing said random quick winbox closings.
What is very weird, it is will happen on one device but not another, and the next day the reverse.
My opinion it was introduced in either the last update to winbox or one of the updates to vers7 along the way.
Looking at the 7.14rc list of fixes, it may be a recognized issue!!

*) winbox - improved connection speed and reliability;

have you tried to change the MTU of your interface back to default? I had the same problem after following this guide and change the MTU. I changed it back and it's good now

have you tried to change the MTU of your interface back to default?

That was it! I had MTU set to 1300 for some reason... Thanks!