Windows formatted and repartitioned ext4 drive

[lou1]

Hello everyone, thanks in advance.

I have a 10TB WD Red HDD i was using for storage. I had 2.5-3TB of data on it. It only had 1 partition (i don’t know if that’s called non-partitioned but i remember that it had a partition table) and it was ext4 all 10TB. Somehow windows partitioned it and now it has 2 partitions, one of them is 16MB NTFS and i don’t know the other but it covers the rest of the drive.

Now i am saving up so i can buy a bigger drive to copy it onto. I’ve heard that it’s the safer thing to do rather than operate on the disk.

I’ve watched some videos about testdisk and ddrescue, but i really don’t know what i should be doing. Please tell me what you think i should know.

I hope this is the proper way to use forums, this is my first time here. I’ve asked the same question on reddit, but the answers were too vague, or maybe i did not give enough information. Please ask if you need more information.

[jode]

Hi lou1! Welcome to Level1Techs!

Re: partition table
All operating systems by default use a partition table, even if the drive just contains a single partition.
There are different ways for partitioning drives:
For a long time (1980s-2010s, basically since the use of BIOS firmware to boot computers) all media (HDDs, flash memory, SD cards, etc.) came formatted with a MBR (master boot record) partition table and a single partition, typically formatted with some outdated windows file system (FAT, FAT32, …), typically for compatibility.
As you can imagine, such an old partitioning scheme has shown its age and generally was replaced with a new way to create partition tables (gpt) when computers transitioned to using a UEFI instead of a BIOS.

Windows, afaik, transitioned as well, with old versions (Windows 95, Windows 7) only knowing MBR partition tables, and newer versions (Windows 10, 11) only understanding gpt partition tables.

Linux understands more types of partition tables (other than MBR and gpt) and you won’t notice a difference unless you searched for it.

So, what exactly happened to your computer and how to fix it?

You say i don’t know the other but it covers the rest of the drive. Does this mean you currently don’t know if this second partition is functional? it was ext4 all 10TB So, did you check if the second partition has a ext4 file system? If you’re currently using Windows, I suggest getting a live Linux iso and booting that from another drive (a USB stick?) - you should be able to mount the partition and find out if your data is still there.

Linux has tools that allow you to modify partitions and partition tables, so, in theory you could

• shrink the existing (ext4?) partition to, say, 4 TB
• create a new partition that is readable from both Windows and Linux (4-5TB NTFS)
• Copy your data from the old to the new partition
• delete the partitions you no longer need
• resize the new partition with all your data to cover the full drive (10TB)

If this sounds like magic to you, continue with your plan of acquiring a new drive and copy your data to that. Don’t attempt the above because a wrong step may cause you to lose your data. I don’t want to be liable for that

If maybe that data has another backup you didn’t mention, or it is not that important to you, boot a linux distro of your choice (again live image from USB stick), install gparted (if not installed by default) and follow the steps above in the gparted interface - one step at a time!

[Strawberry]

“Somehow Windows partitioned it”

Are you certain? Windows does not know how to read ext4 and won’t tell you an ext4 partition is ext4, it will show up as other or unknown. If that tiny partition at the front is actually the EFI partition or gpt protective partition, you might just need to plug that drive into a Linux box to access your old data.

Perhaps. Doing a dd first as you planned is the best practice in any case when you don’t know what your state is and the data is important.

[wr250]

#1 remove the disk from the computer so it does not get written to.You do not want to overwrite any data. reinstall it when the new drive comes so you can try and restore data.
You could dd the drive to a image, or to a new drive and work on that. Testdisk can find old partition tables and restore them if its viable.

#### WARNING ####
dd can and will erase all data. The data will become unrecoverable unless you are a 3 letter us govt agency, and even then they wont get much, just bits and pieces. dd will execute as typed without a “are your sure” prompt. that is why it has the nickname of “data destroyer”.