On Wed, 13 Mar 2019 19:48:01 -0400, Jason
wrote:

My deskside machine has wired ethernet to my router. It has
forever been the case that Windows latches onto the network at
boot every time with no problems until now. I cannot think of
anything I have changed. Perhaps this is the result of an
update, but now when I boot the machine the network connection
does not take place and I have to fiddle with disabling/enabling
the adapter a few times before it does connect. That's not a big
problem, but I'm curious what might cause it. ...and it is not
quite consistent - about one time in five it connects instantly
just like it used to. Hardware diagnostics don't show anything.

Do you have a router? Are you using DHCP? Are you using address
reservation, or whatever your router calls it? When it doesn't connect,
what is your IP address? Is it in the range of 169.254.x.y? Do you have
any other network devices on your LAN? If so, do any of them sometimes
display similar behavior?

If you're using a router and it's configured to use DHCP and the PC ends
up with a 169.254.x.y address, the problem could be the PC or the
router. You can work around that particular issue by configuring a
static IP address (plus netmask, default gateway, and DNS servers) on
your PC. If you set static values, it's one and done. You just need to
take care to assign an IP address that's within your current subnet but
not within your DHCP scope.

The trick is to take a look at your networking info while you're
experiencing the issue. Once you've resolved the issue, it's too late to
do much troubleshooting. Command Prompt "ifconfig /all" would be a good
start, or you can poke around in "Network and Internet Settings", then
"Change Adapter Options", pick the adapter, then select Status from the
context menu.