Note to self: When creating Custom Report Types don't include fields from managed packages that are only installed on the sandbox. It causes your Demployments to fail.
Start Here
If you don't yet fully understand the power of Custom Report Types start with watching this excellent video Learn Salesforce Report Types in 10 minutes!. And some of those tips are also covered in The Hidden Functionality of Custom Report Types - Admin Hero.
Things you learn
- Creating a Custom Report Type based on a Standard Object does NOT create the Report Type the same as the standard report type. Eg Contracts standard report type includes ALL the Account information. A Custom Report Type based on Contract does not. You have to manually add it in. That is highly annoying.
Annoyances
- Taking fields off the CRT is stupid. You have to go to the end of the list of fields in the right hand side box, then drag the field to the blank space. Weird. Stupid.
- Try setting up Custom Report Types in Lightning Setup. It's a window of the old old Salesforce interface inside the old Salesforce interface inside the new Salesforce interface, and it just looks shocking.