Temporarily disabling startup items
According to https://support.apple.com/guide/mac-help/open-items-automatically-when-you-log-in-mh15189/10.14/mac/10.14 (and Mac practice going at least as far back as System 7), holding down Shift on login should disable your startup items. However, I can't seem to manage it. I hold down Shift after I hit Return after entering my password, I hold down shift before hitting Return, I hold down shift and then click on the login arrow, I restart and try again, I use the left or right shift key (haven't tried both at once)…nothing works. All of my startup items launch normally no matter what I do. Obviously my shift keys work, given the presence of capital letters in this post. What could possibly be going wrong here?
MacBook Pro 15", macOS 10.13