I have created two objects School and Teacher. School fields - School name, location, pincode. Teacher fields - Teacher name, salary (number datatype), qualification.
Now i created a rollup summary field for max salary in School object. It created successfully and working fine. Now i wanted to change the datatype of salary from number to currency. It was not allowing me to change the datatype of salary as it was a rollup summary field in School object. So i deleted the rollup summary field in School object. It deleted successfully. But still i am not able to change the datatype of salary, it still shows the error :