Final answer:
The student should check Time Machine preferences, reboot their computer, ensure an external drive is connected, or as a last resort, reinstall Time Machine if necessary to fix the backup issue.
Step-by-step explanation:
When the Time Machine on a Mac fails to complete a backup and presents an alert saying 'No volumes to be backed up were available,' it could indicate several possible issues. Firstly, you should check Time Machine preferences to ensure that it is set up correctly and the designated backup drive is selected. If preferences are set correctly, try to reboot the computer as this can resolve temporary software glitches that may be hindering the backup process. Additionally, make sure to connect an external drive if it is not already connected or if the current drive is not recognized by your Mac. Lastly, while less likely, there may be a need to reinstall Time Machine, especially if the application itself is corrupted, though this step should be considered after other troubleshooting efforts have been exhausted.
Always remember to safeguard your data by ensuring that your backup drives are in good working order and that backups are performed regularly. It is also a good practice to have multiple backup solutions to prevent data loss.