Lost all my Bitcoins?

[Blawpaw]

The 1.21 BC was in a single "chunk". When you sent 0.01, you made a transaction with one "in" (the "chunk") and two "outs": one sent 0.01 to whoever you sent that to, and the other one sent 1.20 back to you as "change". This second "out" was sent to a brand new address that you just generated. Since your old wallet.dat doesn't have the keys to this new address, you don't see it.

That's very odd. This is very similar to doing a backup and restoring it later.  if that actually happened isn't there any way to find out what is this new address?

[lololhyip]

I wanted to test Bitcoin's double-spending protection, so I copied the wallet.dat file to another folder. I had 1.21 BTC as my balance, and I donated 0.01 BTC, and then exited the program. I then moved the copy of the wallet.dat file back to Bitcoin's AppData folder, and started Bitcoin.

When it started, it showed 1.21 BTC as my balance, but a second later, it became 0.00.

Is this there on purpose to punish people who attempt double-spending, or is it a bug?

(All my transactions are present in the window. My balance is at 0.00 though.)

Lost forever?  Sad to hear that.

[arnav95]

i never had a lots of bitcoin but i am a trader and i happen to use a very risky strategy, and every week i loose all of my bitcoins which i make from diversified sources. what i do is i trade on secondstrade, it is a binary options strategy which gives you better odds than compared to the regular binary options brokers.

[Pony789]

The core wallet.dat file now contains pre-generated change addresses to mitigate things like these.

Right.  So why are they not showing.

Does OP simply need to do a restart with -rescan?

Nope a rescan would not help because the keypool feature did not exist yet at the time. This thread was created in July 14, 2010, while the keypool feature was first added to the bitcoin qt by satoshi in October 09, 2010. https://bitcointalk.org/index.php?topic=1414.0.

[SomeBoy]

The 1.21 BC was in a single "chunk". When you sent 0.01, you made a transaction with one "in" (the "chunk") and two "outs": one sent 0.01 to whoever you sent that to, and the other one sent 1.20 back to you as "change". This second "out" was sent to a brand new address that you just generated. Since your old wallet.dat doesn't have the keys to this new address, you don't see it.

Let me see if I got this right. So if you have a certain amount at an address and send out part of that amount, EVERYTHING you had at that address is moved out and the change is deposited at a new address? Why isn't the change kept at the original address?

[franky1]

i never had a lots of bitcoin but i am a trader and i happen to use a very risky strategy, and every week i loose all of my bitcoins which i make from diversified sources. what i do is i trade on secondstrade, it is a binary options strategy which gives you better odds than compared to the regular binary options brokers.

the safe way is not to look for 10% spreads and hoping to double your money over night. just look for 1% spreads, even trading 1 time a day means that you will double your money in 3 months and have 400% profit in a year. and thats just from one trade a day

[Pony789]

Let me see if I got this right. So if you have a certain amount at an address and send out part of that amount, EVERYTHING you had at that address is moved out and the change is deposited at a new address? Why isn't the change kept at the original address?

The major reason is to give users better privacy. If there is no change address, someone else monitoring my address will see how much I have spent my bitcoin every time I make a transaction. But if there is a change address, you will only see I have send some bitcoin to address A and some bitcoin to address B, without knowing which of the two addresses is my change address.

[Furio]

A tiny bit now, but in a couple years?  Here's a snippet from my IRC bot.
According to http://www.census.gov/main/www/popclock.html the world population is 6,855,970,029. If everyone had the same amount of bitcoins, everyone would have 0.00306302 bitcoins.  If 0.00000001 bitcoins were equivalent to US$0.01, then everyone would have equivalent of US$3,063.02389176 and the value of all bitcoins would be equivalent of US$21,000,000,000,000.00.

When Bitcoin gets cracked it will mostly likely to be worth exactly $ 0.00

They havent even cracked sha2 and if the day comes that sha256 can be broken, bitcoin can switch very easily to sha512, sha1024, etc, etc, so no, it wont be broken Destroyed by regulation s maybe, but not the code being broken

[SomeBoy]

Let me see if I got this right. So if you have a certain amount at an address and send out part of that amount, EVERYTHING you had at that address is moved out and the change is deposited at a new address? Why isn't the change kept at the original address?

The major reason is to give users better privacy. If there is no change address, someone else monitoring my address will see how much I have spent my bitcoin every time I make a transaction. But if there is a change address, you will only see I have send some bitcoin to address A and some bitcoin to address B, without knowing which of the two addresses is my change address.

Thanks for replying. So if I have a backup of my wallet.dat file I need to make a new backup every time I send coins, because there's always the possibility that the change will be moved to a newly generated address (if it runs out of pregenerated addresses or something) that doesn't exist in the backup file, right?

[Furio]

Can someone explain me this. If you send it and it changes addresses, you still have the .dat file to which you did the tranfer. If you take THAT .dat file, like stated in the OP, you should have all your funds right, because its the same .dat fi,le as is used with the transaction, since he overwrited it.

What am I missing

[diabolus]

The 1.21 BC was in a single "chunk". When you sent 0.01, you made a transaction with one "in" (the "chunk") and two "outs": one sent 0.01 to whoever you sent that to, and the other one sent 1.20 back to you as "change". This second "out" was sent to a brand new address that you just generated. Since your old wallet.dat doesn't have the keys to this new address, you don't see it.

That's very odd. This is very similar to doing a backup and restoring it later.  if that actually happened isn't there any way to find out what is this new address?

What is odd?

If a writer has written 200 pages of his book and have it in a wordpad-file. Then he removes that file and open the last backup that only contains 50 pages.. well it will only show 50 pages and not 200, this is not odd. Make a backup everytime you use your wallet and save the old backups just in case.

[diabolus]

Can someone explain me this. If you send it and it changes addresses, you still have the .dat file to which you did the tranfer. If you take THAT .dat file, like stated in the OP, you should have all your funds right, because its the same .dat fi,le as is used with the transaction, since he overwrited it.

What am I missing

Yes but he took a old backup and replaced it with the latest wallet.dat after he sent some btc. Make a backup everytime you have sent/received coins.

[NeuroticFish]

Let me see if I got this right. So if you have a certain amount at an address and send out part of that amount, EVERYTHING you had at that address is moved out and the change is deposited at a new address? Why isn't the change kept at the original address?

The major reason is to give users better privacy. If there is no change address, someone else monitoring my address will see how much I have spent my bitcoin every time I make a transaction. But if there is a change address, you will only see I have send some bitcoin to address A and some bitcoin to address B, without knowing which of the two addresses is my change address.

Wow.
Imho such privacy implementation, though very useful for some, should not be the default. Maybe a check box could switch between 2 modes. I know that this is not gonna happen though.
Most users, especially the beginners, especially the people with small amounts, don't need such advanced privacy.
I am glad I don't use btc core, I could have faced this same issue, because I also expected the change go back to the initial address.

Once again, I suggest the newcomers use simpler wallets than the BTC core.

[julian071]

Wow, I did not know that either!! I thought having a backup of my wallet.dat would be enough.... Very useful information, should really be combined with the Bitcoin Core wallet. In fact, if it were up to me I'd have the wallet auto-backup the wallet.dat after every payment.

It's really too bad developing the Core wallet to something actually useful to end-users is so low on the agenda. I really don't understand why =(

[veertje]

......the keypool feature did not exist yet at the time. This thread was created in July 14, 2010, while the keypool feature was first added to the bitcoin qt by satoshi in October 09, 2010. https://bitcointalk.org/index.php?topic=1414.0.

Edit: Found a good answer already from a Gulden (NLG) dev how wallet.dat backups work: https://bitcointalk.org/index.php?topic=554412.msg12623914#msg12623914