MacBook won't respond to restart from the menu

had this a few times, it was a 'save changes?' dialog hiding behind another window, so the restart just sat waiting. command+tab through everything before you force it. if the menu does nothing but the keyboard still works, Terminal with sudo shutdown -r now restarts it cleanly.

Yes, after ten minutes holding the power button is fine. Hold it about 10 seconds until the screen goes off, wait a moment, press it again. The only risk is losing unsaved work, and you've closed everything. Next time it happens, try Option+Command+Esc first. Something stuck in the background (often a sync or backup app) is usually what blocks the restart, and Force Quit will show it.