5.3 - Troubleshooting storage and drive failures
CompTIA A+ Core 1 objective 5.3 covers storage and drive failures. A hard drive that makes clicking noises, is slow to access and shows SMART warnings is failing, so the first action is to back up the data immediately before it dies. A SMART 'reallocated sector' warning likewise indicates the drive is degrading and may fail soon. If a PC's clock keeps resetting and BIOS settings are lost after every shutdown, the cause is a dead CMOS battery (a CR2032). And if a PC reports 'operating system not found' but the drive is not even listed in BIOS, suspect the drive's data and power cabling. Expect scenario questions that describe a failing drive or a missing disk and ask for the correct first response.
Clicking drive + SMART warnings = back up NOW (failing). 'Reallocated sector' = drive degrading. Clock resets + lost BIOS settings = dead CMOS battery (CR2032). Drive missing in BIOS = check data/power cabling.
Practice questions
1. A hard drive makes clicking noises, file access is slow, and SMART warnings appear. What should you do FIRST?
- Defragment the drive
- Back up the data immediately (correct answer)
- Format the drive
- Update the chipset driver
Clicking + SMART warnings signal imminent drive failure — back up data first, then replace the drive.
2. A PC's clock keeps resetting and BIOS settings are lost after every shutdown. What should you replace?
- The system hard drive
- The CMOS battery (CR2032) (correct answer)
- The memory modules
- The power supply unit
A dead CMOS battery loses BIOS settings and the clock when powered off — replace the CR2032 coin cell.
3. A NAS drive shows S.M.A.R.T. 'reallocated sector' warnings. What does this indicate?
- The drive is completely brand new
- The drive is degrading and may fail soon (correct answer)
- The system RAM is running dangerously low
- The installed operating system is corrupt
Reallocated sectors mean the drive is remapping bad sectors — a sign of wear; back up and replace proactively.
4. A PC boots to 'operating system not found' but the drive isn't listed in BIOS. What should you check?
- The connected external monitor
- The drive's data and power cabling (correct answer)
- The installed graphics card
- The keyboard's plugged connection
If BIOS doesn't see the drive, it's likely a connection/power issue or a failed drive — reseat cables, try another port, then test the drive.
5. A RAID 1 mirror shows 'degraded' after one disk failed. What is the correct action?
- Delete the whole mirror array
- Replace the failed drive to rebuild (correct answer)
- Convert the mirror to RAID 0
- Ignore the degraded array state
RAID 1 keeps running on the surviving disk; replace the failed one so the mirror rebuilds redundancy.
6. File reads are extremely slow and the drive is very loud. Which is the BEST immediate action?
- Defragment the loud drive repeatedly
- Back up data now, then replace the drive (correct answer)
- Fully format the failing drive
- Add more system memory (RAM)
Loud noise + very slow reads signal imminent HDD failure — back up first, then replace.