Not only can this problem be solved, it WILL be solved. If anyone can give me insight or idea that leads to solution there's 100 ltc coming your way.
Situation is this: After 3 years I remembered that I have ltc wallet and was very delighted to find 1120 ltc (valued @ 5000 euros atm) inside the wallet. I'm not only broke but in debt, so I immediately tried to send these coins to a market place to cash them out. "The passphrase entered for the wallet decryption was incorrect" I have now been watching this error message for 2 days.
I have 2 versions of the wallet.dat file, both of the same wallet but dates differ. First one has been in AppData\Roaming\Litecoin this whole time and is dated 19:21 12.8.2014. So this is the last time Litecoin core was opened on this computer, before yesterday. Other wallet.dat i found from a usb stick and it's dated 18:32 23.7.2013. This was 1 day after the coins were bought. I have two candidates for password. Both of them were found from old Password Safe file. First one was entered into PWS at 17:43 4.9.2013 and the other at 18:35 on the same day.
I can't comprehend why the first password doesn't open the older wallet.dat file which is dated well before the assumed pw change on 4.9.2013. Neither does the newer version (2014) of wallet.dat open with password entered into PWS at 18.35. Am I doing something wrong when swapping current wallet.dat with one of the backups? I just close litecoin core and replace the old wallet.dat with a new one, open core and see all those shiny coins in balance but no, I just can't send them with neither password or any of the 100s of variations I've tried so far.
This wallet has not been used even once to send coins. This is how the wallet looks like https://imgur.com/a/vQ813 all the coins have been received 1 day before the earliest surviving backup.
Found a piece of paper that has written on it some unrelated passwords from those times. I'm 100% sure that this paper was written after the assumed wallet pw change. After one password there's a comment: "- mark can be / or \ because keyboard is not fully working". There aren't special symbols in the wallet pw candidates but that doesn't exclude the possibility that one of the alphabets on that old keyboard was also malfunctioning. Even if the new password has been typed wrong because of this, the old password should be as it is written in PWS, otherwise pw couldn't have been changed and therefore it should open the wallet.dat dated 23.7.2013. So this whole mess doesn't make any sense to me. I'm missing something here. I had Microsoft Wired Keyboard 600 at the time. This is a long shot but does anyone know what other keys might have been broken if - was turned into / or \ ? Also checked if QWERTZ was turned on and it yielded no results.
Both passwords are really strong. Both are a sentence of five words. This eliminates possibility that they have been typed wrong by accident. New password must be typed twice so the odds for a mistake are astronomical. If somehow this happened, the old password should still work on old backup because the password was changed using the old password and therefore could not have been typed wrong. This is assuming the password indeed was changed as PWS logs indicate.
Tricks that have been tried:
Reinstall from scratch.
Most obvious 1 letter typos including a list generated by a bot.
Checking if the good old Caps lock might have messed up the pw
Cursing and drinking.
Option that I'm planning on going forward with next is trying to brute force one of wallet versions. Which wallet version should I try to break into? Old password has 30 characters including spaces, consists of real words and no capital letters. New password is 23 characters long, consists of real words and the first letter in pw is capital letter.
Are there any theoretical possibility that this is not due to my own mistakes and it's somehow related to a bug in ltc core, problem in my computer or something like that?
https://github.com/gurnec/btcrecover/blob/master/TUTORIAL.md#btcrecover-tutorial does this work with litecoin core?
As a last resort maybe walletrecoveryservices com could help.