Teach students to recognize the sign-in error dialogue box. They need to click the sign out link and sign back in instead of just clicking off it. Google Classroom and other sites that use the Google sign-in will not work with this error message.
Look closely at the screenshot to the left. Do you see the triangle with the exclamation point in the lower right of the task bar? That is the symbol for the sign-in error. If the student has just clicked off the dialogue box, you'll still see that symbol. Have them click the network fan in the lower right corner and then sign out and back in.
Slideshow to use for teaching students how to deal with sign-in errors
Many errors can be fixed by just restarting the device. Click in the lower right corner, click the arrow beside the power symbol, and click restart.
Teach this to all your classes as a first thing they can try before they even raise their hands to ask for help!
No sound
Go to a different site. Is there sound on that site? If so, sound is muted just for the site you can't hear.
Keyboard not typing correctly
Click the battery or fan symbol in the lower right corner to bring up the menu you see on the left
Check to see if the Keyboard setting says US under it. If not, click the arrow in the box to select US English
If this is correct, it may need to be sent off for repair.
As you move the mouse around the image in the top half moves around. This is an accessibility feature called Docked Magnifier. Use Search + Ctrol + D to turn it off.
Whole screen is enlarged. Text is very big and you have to scroll left and right to see everything. Or everything is very small--too tiny to read.
Try Ctrl - to shrink down if enlarged.
Try Ctrl + to enlarge if everything is tiny.
Camera not working
Check site settings. See how here.
Teacher Chromebooks have a slider that will physically cover the camera. If it's your camera that's just black, look along the top edge right above the camera lens. Can you slide the little button to the left? Student Chromebooks do not have this slider.