Security Update 2020-001 High Sierra

Uhhhg, big problems...

Failing hard drive - This machine has a hard drive that appears to be failing.

No Time Machine backup - Time Machine backup not found.

Get an external drive & backup asap.

You eventually want to delete the 2 files in the Clean up: section, but I'd not even use the Mac until you get a backup!

You're not alone. This has been a problematic update for other users. Reference this Apple Community Support page. There's some very good info. on it that should help.

https://discussions.apple.com/thread/251107470

OK, great news & good luck.

All 4 are pointing to xpcproxy, that's a built-in component of OS X's protection.

I'd say a Reinstall of the OS is needed or...

EtreCheck is a simple little app to display the important details of your system configuration and allow you to copy that information to the Clipboard. It is meant to be used with Apple Support Communities to help people help you with your Mac.

http://www.etresoft.com/etrecheck

Pastebin is a good place to paste the whole report...

https://pastebin.com/

Or use the paperclip at the bottom of a Reply to attach the full report here. :)

Workable but harder for me to work with...the Note tool on the bottom of this editor's toolbar, as shown in the image, to copy and paste the output from EtreCheck.