How does file system corruption occur? My Drobo will no longer mount.

Article Id: AA-01292 Last updated date: 08-30-2017

We are sorry you encountered this issue, the good news is this issue can be resolved. 

File System corruption can occur on PCs and Mac's/, on internal or external drives. File System Corruption can occur whether you are connected USB, Thunderbolt, ISCSI or Firewire. It can happen on any drive enclosure, with any drive manufacturer. File System Corruption is not specific to Drobo. 

There are several resources on the Internet that explain how and why file system corruption occurs. Here's one

Ask Leo: Why, or how, do files become corrupt?

What are the symptoms of file system corruption on a Drobo?

  • Drobo Dashboard recognizes Drobo
  • Drive bay lights are all Green
  • Drobo won't mount
  • Volume(s)s are missing

How can I resolve this issue?


  1. In Mac OS Activity Monitor, check to see if HFS_FSCK isrunning, if so your file system is currently being repaired and Drobo will mount once this process completes.
  2. Run Disk Utility > First Aid. Disk Utility is located on your Mac HDD > Applications > Utilities > Disk Utility. NOTE: If you get error "invalid content in the journal" from Disk Utility, try disabling journaling on your Drobo product. Repair your Drobo device with Disk Utility and then turn the journaling back on. 
  3. If Disk Utility is unable to repair Drobo you will need a stronger repair tool, for this we recommend Disk Warrior by Alsoft. Disk Warrior has been in business since 1984 and has a lot of experiencing with file system repair.
  4. Disable Power Nap, this can be found in System Preferences > Energy > Power Nap
  5. If Disk Utility or Disk Warrior is unable to repair it is highly likely the data itself is still present. It is just not readable by your operating system. The alternative to running Disk Warrior is a 3rd party data recovery tool like R-StudioData RescueStellar Phoenix


  1. Run CHKDSK. From the Windows Start Menu > Run >, in box type "cmd.exe" > in box type "chkdsk p:/x" (replace "p" with the drive letter your Drobo device uses in My Computer)
  2. If CHKDSK is unable to repair, it is highly likely the data itself is still present. It is just not readable by your operating system. The alternative is a 3rd party data recovery tool like R-StudioData RescueStellar Phoenix

What causes File System Corruption?

  • Repeated unexpected power outages: These can certainly take a toll on Drobo if this is happening on a consistent basis. Protect your data by using UPS or Surge Protector. 
  • Host Crashes: The host computer may be damaging the file system on your Drobo is you are not properly shutting this down or if the host is rebooting or crashing. Also refrain from leaving your Drobo connected and powered on during operating system updates. Last, third party partition utilities or defrag tools do not work with Drobo and should not be used. 
  • Older drives: While any drive will work with Drobo, we do recommend you check to see which drives work best for your environment. 
  • Improper Shutdown: Proper Shutdown are critical to maintaining data integrity. To properly shutdown your Drobo, see "How do I safely shutdown my Drobo device" If you are using the toggle switch on Drobo to shutdown, ensure that you first properly unmount or eject the volume from your desktop prior to using the toggle switch 
  • Power Nap: Disable Power Nap in System Preferences > Energy > Power Nap

Preventive Maintenance:

  • Follow guidelines for properly shutting down your Drobo 
  • Periodically run CHKDSK or Disk Utility on Drobo
  • If on Mac, ensure you are on latest Mac OS (as of this writing 10.12.6 or later)
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The information contained herein is subject to change without notice.