I am not an Ubuntu power user, but years ago opted for this over Windows and never regretted it.
Recently upgraded from 16.04 to 18 and all was fine until this morning. Logged in first thing, did some work, logged out. Came back later to log in but repeatedly being told password is incorrect. Have restarted multiple times. Can't even log in through the tty.
Please help. I need to get month-end invoices out urgentlyand am now dead in the water.

Ctrl+Alt+F3and see if you can log into the console. This will tell us if your User ID / Password are invalid or if the GUI Login screen is broken. – WinEunuuchs2Unix Aug 27 '18 at 21:42Sign Inbutton there is a gear. After entering your password but before pressingEnterkey, click the gear and make sureUnityis selected. – WinEunuuchs2Unix Aug 27 '18 at 21:48