Windows 11 Upgrade formats my D drive

[Nova8316]

Hi,

I have started the Windows 11 upgrade and ended up with my second hard drive being formated (non allocated in device management). The parition are still correct but my drive didn't showed up in the file explorer and check with the disk management to saw that unwanted behaviour

What is the fastest way to have my data back ?

Is a recovery software like Acronis the only solution to my problem ?

Thanks

[#2]

Only good back up on external drive will over come this issue as you did a format of the d drive.
recovery software will no always recovery files after format very rarely successful.

Sound like the C: drive is one large drive and has never been partition possible sata internal drive which allowed the second hard drive to take drive letter d: possibly SSD drive and your using TPM.

What's happen is the Operating System detected SSD Drive as the main hard drive and installed and configured up on D drive which it thought was C: drive as it did not detect the other hard drive due to the configuration in the bios settings.

i can not see you recovery very well from this my advice is unless you have a back up drive of your previous operating system your buggered and going to have issues in the future if you do not correct the installation pathway now by very clean install of Windows 10 by removing the second hard drive now.

then when you reconnect the second hard drive go to the bios set the order of the two hard drive so you can tell Windows 11 what hard drive you want it on and which partition so you do not lose your files in the future.

[#3]

@Darkmenance 
The C drive is a SSD partitionned with windows 10
I never ever had an update that force to format without my consentement.
So I think there have been one mistake in the way the upgrade was done.

For my data, I will use dedicated software.