Diskpart didn't help me, so I looked for another tool and found TestDisk. However, it requires a lot of technical knowledge, which I don't have at the necessary depth. Depending on whether I select [Intel] or [EFI GPT] as the type, I get different results.
When I choose [Intel] and then [Analyze], I get this output:
When I select [EFI GPT] and [Analyze], I get this:
After performing a [Quick Search], I get some very strange messages. One tells me to check the jumpers because the disk is larger than 4TB, and another displays odd characters and says that no partition was found.
The analysis with [Intel] shows a GPT partition. I assume it needs to be activated somehow or something similar. I just don't see how to do that.
How should I proceed? I lack deeper knowledge about disk structures, etc.
Sorry that the images are being posted here again. Somehow, I didn't understand how to insert them without attaching them.