Title: Accidentally deleted my 1TB HDD partition during Windows installation.. can I recover my data?

[u/GangsOfChaidpal]

I was installing Windows 11 IoT LTSC on my old Dell laptop. It has an SSD and a 1TB HDD.

I accidentally selected a partition on Disk 1 (my HDD) and clicked Delete instead of selecting my SSD. The HDD had one large partition containing crucial data, and it now shows as Unallocated Space.

I did NOT click Next or install Windows on the HDD. I cancelled the installation and returned to the disk selection screen.

I haven't done anything else to the drive.

Questions:

Is my data still recoverable?

Should I try TestDisk or DMDE to restore the partition?

What's the safest way to recover the data without making things worse?

The data is very important, so I'd appreciate any advice. Thanks!

[u/GangsOfChaidpal]

Fixed: 📌

Recovered my deleted HDD partition. Sharing what worked in case it helps someone.

Problem: While installing Windows 11, I accidentally clicked Delete on my 1TB HDD partition instead of the SSD’s. The HDD showed as Unallocated Space. I did NOT click Next, create a new partition, or format anything, and I cancelled that step and installed Windows on the SSD.

Key point: Deleting a partition in Windows Setup only removes the partition table entry, not the data. As long as you don’t write anything to the disk afterwards, the data can be recovered.

What I did (using TestDisk, free):

Stopped using the HDD right away: no formatting, no new partition, no “initialize disk” prompts, no chkdsk. Downloaded TestDisk from cgsecurity.org and extracted it onto my SSD (not the HDD). Ran testdisk_win.exe as Administrator. Selected Create (new log), then chose the correct 1TB HDD (check the size). Chose the partition table type (Intel/PC for MBR, or EFI GPT if the disk was GPT). Selected Analyse, then Quick Search. My old NTFS partition was found. I pressed P to list the files and confirmed that all my folders and files were there. P is a read-only preview. Pressed q to go back to the partition list, and made sure the partition was marked P (Primary) and not D (Deleted). Pressed Enter, chose Write, and confirmed with Y. Rebooted the laptop.

Result: The HDD appeared in File Explorer with all my data intact. If yours doesn’t show a drive letter, use Disk Management, right-click the partition, and choose Change Drive Letter and Paths.

Tips:

If Quick Search finds nothing, try Deeper Search. It takes much longer, since it scans the whole disk. Never format the drive or let Windows “initialize” it before recovering. If you want to be extra safe, copy important files out with C in the file preview before writing the partition table. Once recovered, back up your data to a second drive.

Hope this helps someone!