<p>It seems the -reindex parameter solves the issue.</p>

<p><a href="https://github.com/bitcoin/bitcoin/issues/8081" rel="nofollow noreferrer">https://github.com/bitcoin/bitcoin/issues/8081</a></p>

CC BY-SA 3.0
2018-02-04T09:04:44.667Z
Welcome to BitcoinSE! Please note, the original question states that it is a fork of Litecoin.
Willtech
CC BY-SA 3.0
2018-02-05T11:30:47.503Z
Yes but the -reindex parameter still seems to solve the issue. I had made further explanation at https://stackoverflow.com/questions/47828172/encountering-readblockfromdisk-errors-in-block-header-at-cblockdiskposnfile-0/48606397#48606397 I also am trying to create an altcoin and had stuck at the same ERROR message then applying -reindex parameter at least made it work up to a point where I begin to get Error -28 from rpc call which is said to be "Client is still warming up!" (whatever it means) at https://github.com/bitcoin/bitcoin/blob/v0.15.0.1/src/rpc/protocol.h#L32L87.
Bedri Ozgur Guler
CC BY-SA 3.0
2018-02-06T13:13:59.807Z
Re-Hi to all, i've tried a lot of times with -reindex parameter, but i have the same issue. "ERROR: ReadBlockFromDisk: Errors in block header at CBlockDiskPos(nFile=0, nPos=8) ... ActivateBestChainStep --> Failed!"
Andrea Pizzirani
CC BY-SA 3.0
2018-02-21T12:06:47.337Z
Hello, thx for info. -reindex really take me next step. and now when I run ./xxxcoind -reindex,  it seems stop, debug.log says "potential stale tip detected, will try using extra outbound peer", do you know why and solution?
creator
CC BY-SA 3.0
2018-02-22T05:51:03.847Z
So I googled and added [ -connect=0 ] at last. Then again ReadBlockError occured. So I need to maybe actually mine genesis block inside the code. How? And where put that code? At chainparams.cpp's  before  [ assert(consensus.hashGenesisBlock  ]  line?
creator
CC BY-SA 3.0
2018-02-04T08:44:06.800Z
2018-02-05T11:31:43.923Z
2018-02-05T11:31:43.923Z
Bedri Ozgur Guler
<p>For study and fun I try to create my own altcoin.
I forked Litecoin, removed checkpoints, changed nTime, *pszTimestamp, noNce and hashed new hashes for genesis block in main net, testnet and regressiontest net.
The hardcoded assertions goes OK but when I start the deamon</p>

<pre><code>./src/cryptoind 
</code></pre>

<p>I get alwais the same result:</p>

<pre><code>ERROR: ReadBlockFromDisk: Errors in block header at CBlockDiskPos(nFile=0, nPos=8) ... ActivateBestChainStep --&gt; Failed!
</code></pre>

<p>Going deeper in the code the following statement always fails (main.cpp):</p>

<pre><code>if (UintToArith256(hash) &gt; bnTarget)
</code></pre>

<p>Seems like the genesis block does not respect the difficulty (PoW)</p>

<p>Someone faced the same issue? Thank you all</p>

CC BY-SA 3.0
2018-02-22T05:05:47.697Z
I met same problem. Have you solved? How?
creator
<altcoin><altcoin-development>
ERROR: ReadBlockFromDisk: Errors in block header at CBlockDiskPos(nFile=0, nPos=8)
Andrea Pizzirani
# ERROR: ReadBlockFromDisk: Errors in block header at CBlockDiskPos(nFile=0, nPos=8)

(Asked by: username_0 on 2017-12-31)

For study and fun I try to create my own altcoin.
I forked Litecoin, removed checkpoints, changed nTime, \*pszTimestamp, noNce and hashed new hashes for genesis block in main net, testnet and regressiontest net.
The hardcoded assertions goes OK but when I start the deamon

```
./src/cryptoind 

```

I get alwais the same result:

```
ERROR: ReadBlockFromDisk: Errors in block header at CBlockDiskPos(nFile=0, nPos=8) ... ActivateBestChainStep --> Failed!

```

Going deeper in the code the following statement always fails (main.cpp):

```
if (UintToArith256(hash) > bnTarget)

```

Seems like the genesis block does not respect the difficulty (PoW)

Someone faced the same issue? Thank you all

**Tags:** altcoin, altcoin-development

> **Comments:**
> **username_1**: I met same problem. Have you solved? How?  

---

## 1 answers

### Answer by username_2 on 2018-02-04. Score: 2

It seems the -reindex parameter solves the issue.

<https://github.com/bitcoin/bitcoin/issues/8081>

> **Comments:**
> **username_3**: Welcome to BitcoinSE! Please note, the original question states that it is a fork of Litecoin.  
> **username_2**: Yes but the -reindex parameter still seems to solve the issue. I had made further explanation at https://stackoverflow.com/questions/47828172/encountering-readblockfromdisk-errors-in-block-header-at-cblockdiskposnfile-0/48606397#48606397 I also am trying to create an altcoin and had stuck at the same ERROR message then applying -reindex parameter at least made it work up to a point where I begin to get Error -28 from rpc call which is said to be "Client is still warming up!" (whatever it means) at https://github.com/bitcoin/bitcoin/blob/v0.15.0.1/src/rpc/protocol.h#L32L87.  
> **username_0**: Re-Hi to all, i've tried a lot of times with -reindex parameter, but i have the same issue. "ERROR: ReadBlockFromDisk: Errors in block header at CBlockDiskPos(nFile=0, nPos=8) ... ActivateBestChainStep --> Failed!"  
> **username_1**: Hello, thx for info. -reindex really take me next step. and now when I run ./xxxcoind -reindex,  it seems stop, debug.log says "potential stale tip detected, will try using extra outbound peer", do you know why and solution?  
> **username_1**: So I googled and added [ -connect=0 ] at last. Then again ReadBlockError occured. So I need to maybe actually mine genesis block inside the code. How? And where put that code? At chainparams.cpp's  before  [ assert(consensus.hashGenesisBlock  ]  line?  

---

