Azure VM attach a managed disk without data loss

Question

Hi all I want to swap the data disk from VM1 to VM2, detach & attach is now done at Azure portal. However, when I use "Disk Management" in VM2, found the volume is not mapped yet to any drive e.g. F:\, when I look up the command I find that
https://learn.microsoft.com/en-us/azure/virtual-machines/windows/attach-managed-disk-portal

"you need to format the new disk before you can use it. Select Format disk" which means that everytime I attach a managed disk I need to format it before using it? How can I persist the data then?

Because I'm using Azure Data Box Disk to upload data from on prem DC to Azure as managed disk, if everytime I need to format the disk before using it, this does not make sense to me, there must be a correct way to mount the disk without data loss, can any one shred some light on this? Thank you

Answer 1

You do not need to format a disk if it has already been setup and has data on it (doing so will lose the data). If the disk is showing up in disk management and shows an active volume then all you need to do is assign a letter to it in disk management.