SYMPTOM:
In Strategy 10.x, under Architect Settings the Warehouse Catalog check-box "Disable loading warehouse catalog" is grayed out and cannot be enabled as shown below:

CAUSE:
This issue can occur if the the setting "Read Only Mode" under Schema in Strategy Developer is selected as shown below:

ACTION:
To enable the Warehouse Catalog check-box "Disable loading warehouse catalog", uncheck the setting "Read Only Mode" under Schema in Strategy Developer.