Just a healthy FYI out there to AGP users. Please be careful when upgrading using the in-app upgrade system to 2.7. Be sure to do it at the end of the work day. In my instance it broke my geoprocessing and python tools creating the "failed to create geoprocessing cache" and "failing to load system tools" error message. Trying to remediate may take hours you cannot afford that day.
ESRI does have a help document out there for these error messages.
Unfortunately in my case it will require me to uninstall and reinstall ArcPro. There are other solutions on the geonet to fixing this such as renaming Local/Roaming folders. But i would not recommend that unless your good at keeping your C: drive tidy.
@EricPescatore good warning.
My recommendation is to always do a clean install in the first place...
rename all esri folders in the "users" folders by appending "old" to the name is a good first step "before" reinstalling.
I was excited to install 2.7 after watching the "what's new.." video. I already expected problems from the upgrade, so I waited until the daily work is done. After seeing Dan's advice on performing a clean install, I'm going to take Dan's advice.