Hello.
I started blender this morning and came across a strange issue. One of my meshes has completely borked itself after saving last night. Unfortunately I have no alternative saves available where this issue hasn’t happened:
As you can see, the UV map shows the original topology, but the mesh itself has done something wild. Is there any way to recover the correct mesh?
It’s not the end of the world but it is annoying as it’s about 1.5hrs of work lost otherwise.
you could try the .blend1 file
Unfortunately it’s also broken in that version (I also had a retopo autosave where it is also broken).
I have no idea why this has happened - the mesh was fine, I turned off the collection it was in and then did work on other models. So it has broken at some point after that and I have no idea why as it should not have been selectable or editable.
Oh… that seems nasty…
Did you check the Temp folder if there’s an autosave there that is ok?
Other than than, I don’t think you have any other option then to move the wrong vertices into the correct position by hand. 
UVmaps don’t store the 3D position of the vertices… so reconstructing the mesh from there isn’t an option.
Nice shout - sadly I had a look and there were no saves without the issue.
Oh well, seems like I will to do it again. 
Something similar happened to me a few months ago, but it was the other way around… After a Decimate-unsubdivide, mesh was ok, but lots of face-corners in the UVmap islands were switched… It took me 2 hours to untangle that mess.
