The upgrade likely altered a setting/interaction for the game or network. It could have also corrupted your WMI repository.
Press Windows+Q and type this into the search bar that pops up:
cmd
Right-click on Command Prompt and select Run as Administrator
Enter the following commands into the command prompt window one at a time. Press Enter after each command. Any time you get a confirmation prompt, confirm the prompt. One of the commands may also tell you the WMI service is already started. This is okay.
net stop winmgmt
winmgmt /resetrepository
net start winmgmt
Now, exit the command prompt and restart your computer, then retest running the game…
Onedrive can interfere with and corrupt the settings data for Starcraft. This can happen if Onedrive is set to manage the folder where the settings variable resides in your Documents folder for Windows. Open One drive (reenable if you disabled it) go into settings and deselect the Starcraft Folders under documents so that Onedrive does not try to manage them. Then exit one drive and delete the CSettings.json under Starcraft (Or Variables.txt under Starcraft II) Empty the recycle bin then attempt to launch the game again.
Try doing an extended power cycle on your system. Turn off all devices including the modem. Wait 30 minutes, turn on the modem, wait 5 minutes, turn on any network devices, wait 2 minutes, turn on your computer and try the game.
You can try switching your DNS settings to use a free public DNS servers instead of your ISPs Servers:
We do not have individual steps for specific modems or routers so if you need assistance accessing or updating the devices, contact the device maker/provider.
Sometimes firewall or routing software/hardware will have some advanced settings to prioritize and manage types of network traffic. Normally that is not an issue but we have seen situations where it can interfere with the delivery of the data for our games/voice chat.
Let’s try turning off these features:
QoS
SIP ALG
RoG (ASUS Routers Only)
Security firewalls (Some ISP provided modems)
Not all devices will have these options and the steps for turning these functions off will be different depending on the make/model/software version of the devices and programs involved. If necessary look at the documentation for your security and routing products to find out how to turn these options off.
In some cases there is a corrupt or misconfigured setting within the router or modem. We cannot say what that might be offhand but the easiest way to resolve these conflicts would be to factory reset the router and/or modem.
You may need to look up your specific model for the steps on how to do this and in some rare cases you may need to have this done by the ISP. Feel free to reach out to them for assistance if necessary.
Try running your system in selective startup mode: https://battle.net/support/article/200483
Create a new administrator account: Creating a New Administrator Account - Blizzard Support
Once the account is created, shut down the computer, wait 60 seconds, restart, log into the new profile and try the app/client.