I won't write about these apps and move to what I try first.
Google this: "Windows 10 NETSH RESET" and hope that clears it up. We want to head back to stock when tweaks fail.
You also want to disable update sharing. Noted at https://www.howtogeek.com/224981/how-to-stop-windows-10-from-uploading-updates-to-other-pcs-over-the-internet/
I now realize System Mechanic is trash and uninstalled. I need to manually reconfigure my network/adapter settings but haven't had any success so far.
I have 500 Mbps internet service and 2 Win10 PC's (Dell & HP) that are connected to the same switch. I checked internet speed at Speedtest.net and the Dell was 490 Mbps and the HP 180 Mbps (same test server). I ran SM's Netbooster on the HP and there was no change in speed. I was trying to compare internet settings (there's a report at the end) and ran Netbooster on the Dell and now the Dell slowed down to the same 180 Mbps!!!
I tried resetting to the original network settings and restoring to Windows default through SM and nothing changes...This major pos "Netbooster" did the opposite of what is supposed to do. I did some digging and found that the QoS Packet Scheduler settings may be suspect. I was able to install gpedit.msc and access the Qos settings but that was a dead end.
System Mechanic/Iolo tech support is the worst. The first tech claimed Speedtest.net is unreliable so I requested a different tech. The next tech suggested another program running was causing the problem. The guy spoke broken english and I could tell he was just running down the checklist. I told him he was barking up the wrong tree and then he tried to sell me a premium support plan for $199/yr!
So now I'm kind of stuck and hoping someone here has run into this. Any suggestions would be greatly appreciated.