I appear to be having the same problem as this guy a few months ago.
I neglected to get the private key to one of my old wallets, and now when I try to recover the wallet, it shows up in nanowallet as “mijiln” and “undefined”. I agree with Quantum that it’s almost certainly not a mijiln wallet. It starts with an N, and I never messed around with mijiln, it just shows up that way now when imported into nanowallet (which looks to me like a bug that was either fixed or introduced).
I’m guessing the wallet is corrupted since importing it into nanowallet fails (keeps going back to “wallet needs an upgrade” when I put in the password), and the latest ncc 0.6.91 says it’s the wrong password (I’m absolutely sure the password is correct, I verified it multiple times and used it regularly months ago).
That said, I have one final clue. In my old logs, I note I used to run 0.6.87-BETA release. Is it possible for someone to dig this up if it still exists? It seems unlikely (but not impossible) that my backup wallet files are corrupted the same way and having the same problem, so I wonder if a bug in 0.6.87-BETA yielded a malformed wallet file that can’t be read by later versions.
I appreciate any help! I thought I was fully covered by multiple backups of the wallet file and proven working password, but obviously I was wrong.