Project crashes when opening the file

Hey everyone,

For my project, I had to create a large mountain landscape and after adding the material to this mountain, I copied the entire mountain and saved the file.
After this, the Unreal project crashed and now every time I try to open the project, a crash report pops up.
The crash report is visible in the photo.
Does someone know how to fix this problem?
Can I maybe delete one of the mountains in the project folder?
Or is there a possibility to get back an older version of the file?

Thanks in advance!!