Hello Sharon,
If Password Protected Sharing is turned off, other computers that uses the
Guest account can access shared resources with no username or password
required. If the Guest has a password set, the Guest account doesn't play
guest account role consequently which can cause Password Protection Sharing
to fail to turn off. To resolve this issue, please first check if the Guest
account has a password set by referring to the following steps below.
1. Right click Computer, and click Manage.
2. Under Local Users and Groups, click Users.
3. Right click Guest, click Set Password, and then click Proceed.
4. Leave the password fields blank and click Ok. This will ensure no
password is set for the Guest account.
5. After that, please try turning off Password Protected Sharing to see if
works then.