Q: iTunes back up encryption

I have a huge problem right now , i can't uncheck the encryption iPhone back up .

even i don't  remember that i but a password ( no body use my laptop) .

i tried to delete the old backups and nothing has been changed

i tried to format my laptop and erase every thing on it and it doesn't change .

and there is no profiles in my iPhone setting- general- profile i don't have any profile !!!!!

i tried to delete i tunes from my mac pro it says that mac os required iTunes...

Iphone version: IOS 9.2.1

Mac version : 10.10.5

Please help me .