Hey guys,

Sorry that my first topic is this. I really need help, I transferred 12.9 BTC to my wallet and realized I had set an old passphrase on the wallet. This is absolutely devastating, how can I recover my password?

OK I kinda understand that can't be done but can anyone recommend any password combination software? I have a fair idea of the words used in it but am unsure of the combination.

Cheers

Good thing you found it because the answer is your screwed.  If there was software which could decrypt an encrypted wallet what would be the point of encryption?  Wouldn't the thief just steal the wallet and then decrypt it?

Any good encryption means you lose the key you lost it.

I would write down your password and put it somewhere like a safe.

That's actually not true, as long as the the owner has enough hints about the passphrase, it can be brute-forced quite quickly.
And sometimes even keyboard-brute-forced, as proven here. 

But beware when people send you their wallet for trying to crack the pass, as it's became a new form of scam, they actually send a trojan instead of a wallet.