Bitcoin Forum

So I wanna store all my coins on a 2gig USB, but I am a total noob and technically challenged. Can someone explain step by step how to store coins on a usb or maybe provide a link?

This can't be done if you're using bitcoin-qt, because its data directory needs to be able to store the entire blockchain (10+ GB).

Oh ok. What about if I wanted to store an alt that had less than 10gb blockchain?

run
where F is the drive letter of your USB drive.
more info: https://en.bitcoin.it/wiki/Running_Bitcoin

The coins/keys are in the wallet.dat file. You can put that file on a USB and keep it in cold storage (i.e. offline) but you'll have to move it back to the Bitcoin directory on you computer if you want to spend the coins. However you can receive coins to addresses in the wallet without moving it from cold storage.

I think he wants to 'store his coins' by copying over wallet.dat, not copying the whole blockchain.
Copying over wallet.dat works fine.

I understand that. But you can't simply swap out wallet.dat files. Doing so will cause the client to "miss" transactions that appeared when the wallet was not present.

Edit: rescan happens automatically when swapping wallets so this is no longer an issue.

The client spends a few minutes doing a rescan when you start with a different wallet. No big deal (or is it?)

You can swap out the wallet.dat

Use the -rescan option when starting the client to get the program to look at your transaction record in the blockchain. This will take some time though.

I recommend using http://electrum.org/ if you intend to move wallet files around and want a portable wallet program. The official client is not designed for what you want to do.

EDIT: Also if you use electrum you can create a wallet from a seed and this means you don't have to backup your wallet file multiple times (the seed is enough to recover the entire wallet no matter how many addresses are inside that wallet)

The official client requires the wallet file to be backed up every now and then to save the address pool that is always increasing, the seeded wallets do not have this issue.

just copy the wallet.dat (and encrypt it) on a usb stick and you are fine. you dont need to copy the hole blockchain.

Sooo I backed up the wallet to a usb and deleted the original wallet.dat. But when I try to put it back into the directory, it doesn`t work for some reason :/

Could you explain what you mean by it doesn't work?

It should work

Can you clarify this?   Everybody I know uses this technique without any problem.  Its the most common, and well known technique for storing your BTC safely offline.

You *can* simply swap out the wallet.dat file.  People do it all the time.  

The client does not miss transactions because transactions are not stored in the wallet.dat file.  The client downloads blockchain transactions every time its opened.  The wallet.dat file simply catches up when the two are recombined.

The client will only "catch" the transactions that are in the newly downloaded blocks. It will not add any missed transactions from its existing block store. If you want to do that, you'll need to run the -rescan option.

That's false.
https://en.bitcoin.it/wiki/Data_directory

Rescan runs on its own when you put a new wallet.dat file in.

So can you clarify why you stated you can't swap your wallet.dat file?

Im still not seeing how that statement is not false.

PS:  I didnt mean "no" transactions are stored in the wallet.  I meant the entire transaction history of the blockchain is not exclusively stored there.  You made the statement that you can not swap your wallet.dat file becuase it will miss transactions.  In fact all transactions are updated when you put the wallet file back into the directory. 

Grue,

I think you are mistaken.

I've done this many times myself.  It works.

It requires a rescan but yeah it works

It used to be the case that a rescan was required after swapping wallets. That was the only issue I had with changing wallets. Now it's automatically rescanned so it's no longer an issue. I edited my post to reflect that.