Trap: External hard disks with native 4K sector size

Amazon[German]Just a brief information for people who maintain larger system inventories with external hard disks. There seems to be a problem: More and more manufacturers only supply external hard disks with 4K sector size. This could lead to serious issues with backup devices under older operating systems.


The problem: Older operating system and sector size 4k

From mid-2010 until the beginning of 2011, hard disk manufacturers are starting to introduce new product models that work with 4 KByte sectors instead of the usual sector size of 512 bytes in the last 3 decades. This advanced format with the 4 KB sector size enables more efficient storage of ECC data for error correction.

What happened silently can cause serious issues for users. I had covered this within my 2011 German blog post Problembär: Neue Harddisks mit 4K Sektoren after a hint from a reader. At that time Windows XP was still common and some people already was on Windows 7. Because older operating systems like Windows 7 SP1 or Windows Server 2008/R2 (to mention the versions still in maintenance) can only work with hard disks that have a sector size of 512 bytes. As of Windows 8, this size limit is no longer given. 

Tools for partitioning, backing up or cloning hard disks can bypass the Windows API for hard disk access and thus cause issues. If the tool does not know the new extended format with the 4 KB sector sizes, some things can go wrong when partitioning, copying or backing up. Microsoft later released a hotfix KB982018 for Windows 7 and Windows Server 2008 R2 SP1 to mitigate the problem. I mentioned this in my old German blog post Hotfix (KB 982018) für 4K-Sektor-Festplatten in 2011.

The topic comes up again

I had already seen the topic a few days ago at German site and I have planned to mentioned it here briefly. Then the creator of the post mentioned contacted me and asked for email addresses of hard disk manufacturers. So it was a trigger to cover this topic immediately. In the German article Externe Festplatten nur noch mit nativer 4k Sektorgröße erhältlich? the user with the alias the buccaner addresses a problem he was facing. He writes there (below is my English translation):

External hard disks only available with native 4k sector size?

For a long time, the manufacturers did not deliver their larger hard disks with the “real” 4K sector size for compatibility reasons, but emulated a virtual sector size of 512 bytes via the 512e format. Older operating systems can also work with this, provided the patch is installed.

But this seems to be finished without much fuss. The hard disks come more and more in the “Native 4K Format”.

This can cause serious issues when using external hard disks for backups. I mentioned it in the text above – the tools often bypass the logical structures of the operating system. On, the article creator describes a case in which he ran into serious issues.


  • Scenario: Replacing External Backup Disks for a Windows Server 2008
  • Problem: Backup aborts suddenly with I/O error messages

User the buccaner explains some details about the root cause of this failure within the German article. But it can be drilled down to: We still need external hard disks, that emulates 512 byte sector size. And he is facing the problem, that he has to select external hard disks for his backups that works. Currently he use a kind of trial-and-error procedure, which isn’t satisfying.

Question 1: How do you solve this problem in your environment – if affected?

Question 2: The buccaner wrote here that he wants to start a request with manufacturers, to check, which vendors still offering external hard disks with 512 byte sector size. For this he needs direct e-mail contact addresses of hard disk manufacturers, where he would like to ask. Can you support him with mail addresses? If you have a a direct e-mail contact address, leave as a comment here. Thank you.

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