Quote from: noobs on December 04, 2017, 03:38:33 PM

Hi there, apologies in advance for this long and technically naive post!

I bought some Bitcoin a few years ago and stored them in a Multibit wallet on my Mac. I have 2 versions of Multibit stored - v0.5.15 and v0.5.18. The wallet is saved on an old Mac that I no longer use.

I have barely looked at the wallet since then. My intention was to buy and hold as a speculative investment. I once transferred the BTC out of the wallet onto Coinbase and then back again within a few minutes but aside from that, the wallet has not been used for anything other than storage.

After seeing the market value of BTC climb steeply during the last few weeks I logged onto the old Mac and opened Multibit v0.5.18. I learned that Multibit has been out of support for some time and that I needed to transfer the BTC to a new wallet. The wallet wouldn't sync with the Network but I read instructions online for creating a private key that I could then use to 'sweep' the BTC into a new wallet with.

When I tried to create a private key I found that I was being asked for a password. I don't remember ever setting a password for the wallet, nor do I remember needing to use a password when transferring to Coinbase and back. I have spent the last 48 hours searching everywhere for a record of a password but have found nothing. This is very very unusual for me - I have a tried and tested system of emailing abbreviated versions of important info like passwords to myself but cannot find any such record for the Multibit wallet. I might be wrong, but I'm almost certain that I never set one. I've also tried countless variations of my main passwords but they have all been rejected.

I also tried opening v0.5.15 of the Multibit software and it behaved differently to v0.5.18. Firstly, it synced with the network quite quickly (v0.5.18 hadn't even started to sync after having it open for several hours). Secondly the wallet appeared temporarily without a password being set. I was able to generate a private key without inputting a password and the option to "add password" appeared in the drop down menu. This clearly indicates at the very least that it was possible to create wallets in Multibit that were not password protected but I think it also indicates that my wallet did not have a password. However, I've tried sweeping the wallet with the private key into other wallets and it's either not been recognised or has indicated that no funds are in the source wallet. I've checked the wallet on bitref and it shows the the BTC is still stored in there.

I've got a horrible feeling that this means that I won't be able to recover my bitcoin. I'm not very tech savvy so struggle to follow the discussion on a lot of the Bitcoin message boards that I've looked at. I suppose my key questions are:

1. Does anyone know of a bug in the versions of Multibit that I've been using, which would 'impose' a password? If so, could a standard password have been applied?

2. I saw somewhere that it might be possible to discern either the password or the private key from the underlying data files. Having exported and imported the BTC, I have the transaction records but wouldn't know where to start to try and decrypt them, if such a thing was even possible.

Thanks for reading. If anyone has any smart ideas I'd be extremely grateful!

Do u still have the issue? I made research about Multibit Classic wallet password change issue so far and developed a program to handle the problem.
Please check this link https://docs.google.com/document/d/1KNeCINN9EAgzGX9z0jlFZg6CTCicOmfYfemzNfdZe4Q/edit?usp=sharing

Let me know if you still have those issues.