Mac users may experience issues with the keyboard as some keys may stop working. For example, the B key on the Mac keyboard may stop working. Replacing the keyboard may not solve the issue. This could happen for various reasons, such as the mouse key function has been turned on, etc. The problem of a particular key of the Mac keyboard not working could be related to a setting in the operating system for speech. Disabling the "speak selected text" option may help solve the issue if the B key of the Mac keyboard does not work.