<p>Okay, based on the comments I have tried a couple of things but in the end only the following worked:</p>

<ol>
<li>Close Bitcoin client</li>
<li>Backup files from %APPDATA%\Bitcoin</li>
<li>Optional:Download Block chains from:     <a href="http://sourceforge.net/projects/bitcoin/files/Bitcoin/blockchain/" rel="nofollow">http://sourceforge.net/projects/bitcoin/files/Bitcoin/blockchain/</a> to prevent lengthy initial download <strong>(Warning: the link advises against doing this if you have transactions in your wallet).</strong></li>
<li>Start Bitcoin client with the
<code>-rescan</code> option from command line. </li>
</ol>

<p>After that the client started downloading blockchains again. This worked for me. Not sure if this will work for everyone.</p>

CC BY-SA 3.0
2012-02-20T10:17:23.377Z
2012-02-20T23:01:23.440Z
2012-02-20T23:01:23.440Z
Patrick
<p>I had a similar problem, but the <strong><em>-rescan</em></strong> option didn’t help.</p>

<p>In my case, there were a lot of lines referring to orphan blocks in my <em>debug.log</em> file (not 100 % sure it’s related but it may):</p>

<pre><code>2014-08-18 20:52:57 ProcessBlock: ORPHAN BLOCK 0, prev=00000000000000001132f6ac32387e51960e3154b2ad4420bdeb64d77999388f
2014-08-18 20:54:00 ProcessBlock: ORPHAN BLOCK 1, prev=00000000000000000e9926124cabed78be0ae8bab22fb20acc643e94749120f8
2014-08-18 20:56:37 ProcessBlock: ORPHAN BLOCK 2, prev=00000000000000001b3f790fc107051c17702d305b08a3ae6325f40ecf44eae9
...
</code></pre>

<p>Finally, I tried to restart the client with the <strong><em>-reindex</em></strong> option which fixed my problem (but took 100 % of my CPU usage for several hours while reprocessing the blockchain).</p>

<p>So if the rescan option don’t work, don’t give up, try the reindex option!</p>

CC BY-SA 3.0
2014-08-19T21:21:38.307Z
2014-09-05T12:45:30.920Z
2014-09-05T12:45:30.920Z
paulgreg
<p>You should update your bitcoin software.
Old bitcoin versions are not supported.</p>

<p>Look here:
<a href="https://bitcointalk.org/index.php?topic=55852.0" rel="nofollow">https://bitcointalk.org/index.php?topic=55852.0</a></p>

CC BY-SA 3.0
2012-02-20T16:05:45.750Z
It's true that regularly upgrading is encouraged, but all clients since 0.2.10 have supported to switch that happened on Februari 20th.
Pieter Wuille
CC BY-SA 3.0
2012-02-20T15:46:14.810Z
2012-02-20T15:46:14.810Z
Alex Saver
<p>I had this happen to me once. It was apparently caused by an incompatible peer node. </p>

<ol>
<li>Delete <code>$HOME/.bitcoin/peers.dat</code></li>
<li>Restart <code>bitcoind</code></li>
</ol>

<p>Afterwards, new compatible peers will be found, and hopefully, you'll start processing blocks as expected again.</p>

CC BY-SA 3.0
2017-08-23T02:52:57.147Z
2017-08-23T02:52:57.147Z
Ryan McGeary
<p>I hadn't started/used my Bitcoin client for ages. Now, whenever I start the client, it is downloading <code>block 135407</code> and does <strong>not</strong> progress past it.</p>

<p>What can I do?</p>

CC BY-SA 3.0
2012-02-20T09:06:05.770Z
See http://bitcoin.stackexchange.com/questions/2914/ for some things to try.
Meni Rosenfeld
CC BY-SA 3.0
2012-02-20T09:46:53.507Z
What version of the client?
Stephen Gornick
CC BY-SA 3.0
2012-02-20T10:18:08.367Z
thanks. I did try things mentioned in the other answers. I posted an answer to this question. @StephenGornick: I am using the latest 0.5.2 client.
Patrick
<bitcoin-core><blockchain><synchronization><canonical-question>
What can I do when the blockchain synchronization is stuck at a specific block?
Patrick
# What can I do when the blockchain synchronization is stuck at a specific block?

(Asked by: username_0 on 2012-02-20)

I hadn't started/used my Bitcoin client for ages. Now, whenever I start the client, it is downloading `block 135407` and does **not** progress past it.

What can I do?

**Tags:** bitcoin-core, blockchain, synchronization, canonical-question

> **Comments:**
> **username_1**: See http://bitcoin.stackexchange.com/questions/2914/ for some things to try.  
> **username_2**: What version of the client?  
> **username_0**: thanks. I did try things mentioned in the other answers. I posted an answer to this question. @username_2: I am using the latest 0.5.2 client.  

---

## 4 answers

### Answer by username_6 on 2017-08-23. Score: 6 | Accepted answer

I had this happen to me once. It was apparently caused by an incompatible peer node.

1. Delete `$HOME/.bitcoin/peers.dat`
2. Restart `bitcoind`

Afterwards, new compatible peers will be found, and hopefully, you'll start processing blocks as expected again.


---

### Answer by username_0 on 2012-02-20. Score: 4

Okay, based on the comments I have tried a couple of things but in the end only the following worked:

1. Close Bitcoin client
2. Backup files from %APPDATA%\Bitcoin
3. Optional:Download Block chains from: <http://sourceforge.net/projects/bitcoin/files/Bitcoin/blockchain/> to prevent lengthy initial download **(Warning: the link advises against doing this if you have transactions in your wallet).**
4. Start Bitcoin client with the
   `-rescan` option from command line.

After that the client started downloading blockchains again. This worked for me. Not sure if this will work for everyone.


---

### Answer by username_3 on 2014-08-19. Score: 2

I had a similar problem, but the ***-rescan*** option didn’t help.

In my case, there were a lot of lines referring to orphan blocks in my *debug.log* file (not 100 % sure it’s related but it may):

```
2014-08-18 20:52:57 ProcessBlock: ORPHAN BLOCK 0, prev=00000000000000001132f6ac32387e51960e3154b2ad4420bdeb64d77999388f
2014-08-18 20:54:00 ProcessBlock: ORPHAN BLOCK 1, prev=00000000000000000e9926124cabed78be0ae8bab22fb20acc643e94749120f8
2014-08-18 20:56:37 ProcessBlock: ORPHAN BLOCK 2, prev=00000000000000001b3f790fc107051c17702d305b08a3ae6325f40ecf44eae9
...

```

Finally, I tried to restart the client with the ***-reindex*** option which fixed my problem (but took 100 % of my CPU usage for several hours while reprocessing the blockchain).

So if the rescan option don’t work, don’t give up, try the reindex option!


---

### Answer by username_4 on 2012-02-20. Score: -1

You should update your bitcoin software.
Old bitcoin versions are not supported.

Look here:
<https://bitcointalk.org/index.php?topic=55852.0>

> **Comments:**
> **username_5**: It's true that regularly upgrading is encouraged, but all clients since 0.2.10 have supported to switch that happened on Februari 20th.  

---

