Error mounting system-managed device /dev/sda2: unknown filesystem type 'NTFS'

Hey everyone,

I just tried to reduce the size of the main partition on my old HDD (I used it in my old PC which is why it is NTFS) using KDE partition manager and… something went wrong. I am not sure what because it did not give me a proper error message during the re-partitioning itself.
I undertook 3 operations

  • reduce the partition by ~50gb
  • reduce it further by ~450 gb
  • turn the freed space into a new one and mount at a specified location

the first part seems to have gone through as I now have a separate 50gb partition in ext4, and I assume during further reducing the initial partition the error must have occurred.
And now, the initial volume cannot be mounted anymore…

as you can see from this screenshot below, I already did the same thing without any issues a few days ago… so I am not quite sure what went wrong this time - and more importantly, how to fix it :confused:
I am not allowed to insert media or links so I had to get a little bit creative:
https:// abload. de/img/screenshot_20210303_24pjpm.png

some more information:
there is about 1 tb of data on the NTFS partition, so there should have been plenty of free space left.
the data on there is somewhat important…

I hope my explanations weren’t too confusing and I am glad for any help I can get!
Thank you in advance!