Which of the following is a sign that your hard drive may be failing?

Frequent error messages and slow performance are indeed significant indicators that your hard drive may be failing. When a hard drive begins to fail, it often results in errors during data read/write operations, leading to the operating system generating error messages. Additionally, the overall performance of the computer can degrade as the hard drive struggles to access data efficiently. Slow performance could be due to the hard drive's inability to retrieve or save files correctly, coupled with the possibility of bad sectors emerging on the drive, which can slow down data access times considerably.

The other options are not associated with failing hard drives. Quick boot times, increased available storage, and stable system performance suggest that the hard drive is functioning well, rather than deteriorating. A healthy hard drive typically exhibits any combination of these positive characteristics. This makes the first choice the most telling sign of potential failure, highlighting the importance of monitoring your system’s performance and error messages for early detection.