How to create a new transaction security policy?

Hey Casey, 

Salesforce release notes confirm the exact cause: there's now a "Modify Transaction Security Policy" permission required to create, delete, and update Transaction Security Policies, and users with only the Customize Application permission (which is what most admin users had relied on before) are now restricted to view-only access. That's almost certainly why New is greyed out for you, even as a System Admin, if this permission isn't explicitly on your profile/permission set. 

Fix: 

1. Setup > Profiles (or Permission Sets) > find your user's profile 

2. Search System Permissions for "Modify Transaction Security Policy" 

3. Enable it, save 

4. Go back to Transaction Security Policies, New should now be clickable 

If you're on a Trailhead Playground and can't edit the System Administrator profile's permissions directly for some reason, try assigning yourself a permission set with this permission checked instead. 

Reference: