Catalina high CPU usage (nsurlsessiond, WindowServer, trustd)

The solution is here:

https://discussions.apple.com/thread/251258165?answerId=252448239022#252448239022

Resetting PRAM/NVRAM worked but only for a short time... maybe an hour or less then I heard my fans going nuts and CPU temp shot up to 150 degrees (smcFanControl to see temp) and Activity Monitor was showing nsurlsessiond was back at 60% of CPU usage. BTW, I'm on a mid-2012 MacBook Pro 15" Retina. I read lots of folks reinstalling a fresh OS but I'm trying to avoid doing that. I found the following and so far it's working:

(Main thread) nsurlsessiond, trustd, syslogd high CPU

https://discussions.apple.com/thread/251258165?answerId=252527520022&page=1

I read through the entire main thread (linked above) and specifically followed these instructions:

https://discussions.apple.com/thread/251258165?answerId=252960046022#252960046022

Similar issue on my 27'' iMac end 2015 after migration from El Capitan to Catalina. According to activity monitor the process "nsurlsessiond" (of user "_nsurlsessiond") produces about 62% CPU load, there is only minor usage of network, hard disk, and memory.

Similar issue on my 27'' iMac Late 2012 after migration from El Capitan to Catalina. According to activity monitor the processes: "nsurlsessiond" (of user "_nsurlsessiond") produces about 62%, trustd - 40%, syslogd - 33%, launchd - 21% (of user "root") CPU load, there is only minor usage of network, hard disk, and memory.

I had the same thing with my mid 2012 Macbook Pro. It was running painfully slow on Yosemite (yes I was really that far behind) so I upgraded to Catalina, which pretty much rendered by Macbook useless due to the high CPU usages of nsurlsessiond etc. I also, very foolishly, did not realise that Catalina no longer supported 32bit software. This meant CS6 and few old game no longer run.

No idea what causes the nsurlsessiond etc. - I tried several time to resolve the issue and searched the apple forums for advice but to no avail. In the end I came to the conclusion that the hardware on my Macbook Pro is not sufficient, even though it's listed as compatible. I've completely wiped my Macbook and reinstalled El Capitan, and it's running faster than ever (and CS6 works fine). Obviously El Capitan is unsupported so there are security risks, but I can't afford an upgrade at the moment so I'll take the chance.

Hopefully Apple with issue an update to fix the excessive CPU usage as it does seem to be affecting a lots of people.

I had this same issue or nsurlsessiond process and trustd process taking majority of CPU time/ cycles in my Mac Mini after upgrading to Mac OS X Catalina. What fixed issue for me was to reset PRAM/NVRAM.

"Reset PRAM/NVRAM – Restart your Mac. After it is turned on, as soon as you hear the startup chime, press Option, Command, P, and R keys together and hold them until the Mac restarts again."

Hope this helps some one looking for an answer.