Synology NAS Error Code 42: How to Fix It

Easy 15-30 minutes Medium Severity Verified June 2026
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Error Code
42
Brand
Synology
Product Type
nas
Severity
Medium
DIY Difficulty
Easy
Estimated Fix Time
15-30 minutes
Synology error code 42 indicates that your NAS cannot detect the installed memory (RAM). This often happens after a power surge, improper shutdown, or physical disturbance. The fix typically involves reseating the RAM modules, testing with one module, or replacing faulty memory.
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Tools You'll Need

How to Fix Error Code 42

  1. Power Off and Unplug the NAS

    Always unplug the device before opening the case to avoid electric shock.

  2. Open the NAS Chassis

  3. Remove and Reseat the RAM Modules

    Handle RAM modules by the edges to avoid static damage.

  4. Test with Minimal Configuration

  5. Check for Damage or Corrosion

  6. Replace Faulty RAM Module

Parts You May Need

Synology-compatible DDR3/DDR4 SO-DIMM RAM
Check Price on Amazon
Synology-compatible DDR3/DDR4 SO-DIMM RAM
Check Price on Amazon
Synology-compatible DDR3/DDR4 SO-DIMM RAM
Check Price on Amazon
Synology-compatible DDR3/DDR4 SO-DIMM RAM
Check Price on Amazon
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When to Call a Professional

If reseating and testing all RAM modules individually does not resolve the error, the motherboard may be faulty. Contact Synology support or a professional technician for further diagnostics.

Frequently Asked Questions

What does Synology error code 42 mean?
Error code 42 means that DSM cannot detect the memory (RAM) in your NAS. It usually occurs after a hardware change or power issue.
Can I use any RAM with my Synology NAS?
No, Synology NAS requires specific RAM types (DDR3 or DDR4 SO-DIMM). Check your model's compatibility list before purchasing replacement RAM.
Will resetting DSM fix error 42?
No, error 42 is a hardware detection issue. Resetting DSM will not fix it; you need to address the physical RAM.
How do I know if my RAM is faulty?
Test each RAM module one at a time. If one module causes the error and the other doesn't, that module is faulty. Also listen for beeps — no beeps may indicate no RAM detected.
Is it safe to open my Synology NAS?
Yes, but unplug the power first and handle components carefully to avoid static damage. Opening the case does not void the warranty for most models.

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