user14215: So I have downloaded Bitcoin-QT v0.8.6-beta.
It has downloaded everything and now this folder:
C:\Users\user\AppData\Roaming\Bitcoin\blocks

is 17GB
Anyway to prune/delete something?

user13413: There's no way to make this smaller. Deleting the files here will cause your node to crash. If space is a problem use a lite client like Electrum or Multibit which does not require a blockchain download.

user11253: The 17 GB of data in your blocks folder is the blockchain. This is the public ledger of all transactions in the Bitcoin network, from day one. A full node needs all this data to check each new block that arrives from the network. As time goes on, the size of the blockchain will only increase.
There exist other clients such as MultiBit which do not require the full blockchain download. These are called SPV or Simplified Payment Verification clients.

14215: <p>So I have downloaded Bitcoin-QT v0.8.6-beta.
It has downloaded everything and now this folder:</p>

<pre><code>C:\Users\user\AppData\Roaming\Bitcoin\blocks
</code></pre>

<p><strong>is 17GB</strong></p>

<p>Anyway to prune/delete something?</p>
 13413: <p>There's no way to make this smaller. Deleting the files here will cause your node to crash. If space is a problem use a lite client like Electrum or Multibit which does not require a blockchain download.</p>
 11253: <p>The 17 GB of data in your <code>blocks</code> folder is the <em>blockchain</em>. This is the public ledger of all transactions in the Bitcoin network, from day one. A full node needs all this data to check each new block that arrives from the network. As time goes on, the size of the blockchain will only increase.</p>

<p>There exist other clients such as <a href="https://multibit.org/" rel="nofollow">MultiBit</a> which do not require the full blockchain download. These are called SPV or <a href="https://en.bitcoin.it/wiki/Scalability#Simplified_payment_verification" rel="nofollow">Simplified Payment Verification</a> clients.</p>
