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Issue reattaching data disk to Azure VM after changing it from Premium SSD to Standard HDD

Eric Andrade 0 Reputation points
2025-08-11T23:41:51.4766667+00:00

Hello,

As my title describes, I'm unable to reattach my data disk drive to the Azure VM it was previously assoicated with. I had to detach the disk in order to change the storage type that it was using from Premium SSD with ZRS to a Standard HDD with LRS to reduce cost. I already successfully made the change to the new storage type, but now I cannot add the disk back to the VM. When I try to find the disk with the "attach existing disk" option it just shows up blank in the search bar area when I type in the name. I know the disk still exists because I can see it in the resource group it belongs to.

Has anyone else run into this issue before?

Azure Virtual Machines
Azure Virtual Machines
An Azure service that is used to provision Windows and Linux virtual machines.
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  1. Vinodh247 36,031 Reputation points MVP Volunteer Moderator
    2025-08-12T01:01:25.46+00:00

    Hi ,

    Thanks for reaching out to Microsoft Q&A.

    Yes, this happens in Azure when the disk's region, availability zone, or encryption settings no longer match the VM's configuration after you change its storage type. The fact that it does not show up under Attach existing disk is because Azure filters out disks that are incompatible with the selected VM. First, check region and zone alignment, that is the most common blocker after moving from ZRS to LRS. If the disk’s location or zone does not match, take a snapshot and recreate the disk in the VM’s exact location and availability zone.

    Other common reasons why this happens:

    1. Region mismatch
    2. Availability zone mismatch
    3. Encryption or key mismatch
    4. Disk state
    5. Azure Portal caching

    Please 'Upvote'(Thumbs-up) and 'Accept' as answer if the reply was helpful. This will be benefitting other community members who face the same issue.

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