Is there an option to set a default "Color Theme" for all users in SANDBOX?

Only by Role, in the Role record, there is a preference subtab, you can set it there, but keep in mind, the user can override it in their Set Preferences. I have not found a way to lock it.

Thanks a lot for the information. It looks I will have to do this by role then. Thank you

That's good info! I always change my color so i don't accidentally blow away something in production.

We set all roles to use Pink for the color, that way there is no way you do not know your in SBX vs Prod.

I go with Saint Johns Red... I guess the only negatives are that you have to modify the roles every time you do a refresh and can't set the color theme for Admin role. Small price to pay for best practices...