While having the logs of what Minecraft is having trouble with would help work out exactly what is wrong. To me, this just seems like a level.dat problem where the game just can't read the world metadata in order to display it.
I've fixed many worlds by aquiring a complete level.dat and replacing the broken one, so my first thought would be backing up the broken world folder to an explicitly named folder (via copy-paste) to keep from any irreversible damage, and, within the original broken world inside your saves folder, rename "level.dat" to "level.dat_broken" then rename "level.dat_old" to "level.dat" and see if the world is displayed in the saves list.
I just know how attached you can get to worlds, so I would hate for this guy to be left with 'oh my world is corrupted' when the actual world data may be fine.
Oliver Briggs
While having the logs of what Minecraft is having trouble with would help work out exactly what is wrong. To me, this just seems like a level.dat problem where the game just can't read the world metadata in order to display it.
I've fixed many worlds by aquiring a complete level.dat and replacing the broken one, so my first thought would be backing up the broken world folder to an explicitly named folder (via copy-paste) to keep from any irreversible damage, and, within the original broken world inside your saves folder, rename "level.dat" to "level.dat_broken" then rename "level.dat_old" to "level.dat" and see if the world is displayed in the saves list.
I just know how attached you can get to worlds, so I would hate for this guy to be left with 'oh my world is corrupted' when the actual world data may be fine.