<p>Delete your <code>chainstate</code> and <code>blocks</code> folder and start Bitcoin-Qt again. It will then re-sync your blockchain.</p>

CC BY-SA 3.0
2015-08-18T13:13:40.763Z
2015-08-18T13:13:40.763Z
Jonas Schnelli
<p>Forget about the bootstrap file. That's old and obsolete information.</p>

<p>Did you turn off bitcoin-qt every time before you copied or deleted files?</p>

<p>You may need to just let bitcoin-qt re-download the whole blockchain. Make sure you backup your wallet (wallet.dat).</p>

CC BY-SA 3.0
2015-08-18T13:12:55.747Z
2015-08-18T13:12:55.747Z
Jannes
<p>I wanted to back up the blockchain on my hard drive as it took around 50 GB on my laptop. I did so and deleted all the <code>blk000.dat</code> and the <code>rev000.dat</code> from (<code>~/Library/Application Support/Bitcoin/</code>) which are saved on my hard drive. Apparently this was a stupid mistake as I cannot open Bitcoin QT anymore. I therefore re-transfered everything back to the same folder. But nothing happens, and Bitcoin Core does not open. </p>

<p>After looking around, many are mentioning a <code>bootstrap.dat</code> file which correspond to the block chain. I cannot seem to find this file anywhere on my laptop.</p>

<p>Any clues? thanks a lot!</p>

<blockchain>
Wanted to back up blockchain to save space, now I cannot open bitcoin QT?
I.P
# Wanted to back up blockchain to save space, now I cannot open bitcoin QT?

(Asked by: username_0 on 2015-08-18)

I wanted to back up the blockchain on my hard drive as it took around 50 GB on my laptop. I did so and deleted all the `blk000.dat` and the `rev000.dat` from (`~/Library/Application Support/Bitcoin/`) which are saved on my hard drive. Apparently this was a stupid mistake as I cannot open Bitcoin QT anymore. I therefore re-transfered everything back to the same folder. But nothing happens, and Bitcoin Core does not open.

After looking around, many are mentioning a `bootstrap.dat` file which correspond to the block chain. I cannot seem to find this file anywhere on my laptop.

Any clues? thanks a lot!

**Tags:** blockchain


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## 2 answers

### Answer by username_1 on 2015-08-18. Score: 1

Delete your `chainstate` and `blocks` folder and start Bitcoin-Qt again. It will then re-sync your blockchain.


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### Answer by username_2 on 2015-08-18. Score: 0

Forget about the bootstrap file. That's old and obsolete information.

Did you turn off bitcoin-qt every time before you copied or deleted files?

You may need to just let bitcoin-qt re-download the whole blockchain. Make sure you backup your wallet (wallet.dat).


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