<p>Your blockchain is corrupted. In Bitcoin Core's datadir, go to the blocks folder. Delete the file named <code>blk0075.dat</code> and ever <code>blk*.dat</code> file with a higher number. Also delete <code>rev0075.dat</code> and every <code>rev*.dat</code> file with a higher number. Start Bitcoin Core, it will need to reindex. At this point, it should begin building the block databases, and it will then download the blocks that you deleted once it gets to that point.</p>

CC BY-SA 4.0
2019-08-09T02:53:33.297Z
If he deletes block files corresponding to already active blocks, he'll need a reindex from scratch anyway.
Pieter Wuille
CC BY-SA 4.0
2020-11-26T09:56:29.673Z
Why is it necessary to delete the following files? I have this error on my first file after moving them from SSD to HDD. However, I have the error at height 255, not at height 0. So part of the first file seems correct. I thought I just move this one file from another backup I have and it could work without reloading all the others.
bomben
CC BY-SA 4.0
2020-11-26T17:22:14.080Z
Deleting the files is necessary if one or more blocks stored in the files are corrupted. Either your backup is corrupted, or the file was corrupted in transit. Typically there isn't any need to delete anything or to reindex.
Ava Chow
CC BY-SA 4.0
2019-08-09T00:32:01.457Z
2019-08-09T00:32:01.457Z
Ava Chow
<p>Hello after I got an db error.. I try to reindex my db. But I got this error:</p>

<p>ERROR: ReadBlockFromDisk: Errors in block header at FlatFilePos(nFile=75, nPos=117947311)</p>

<p>So what can I do to fix it ?</p>

<p>System:
4 cores
2 GB RAM
500GB ISCI Storage</p>

CC BY-SA 4.0
2019-08-06T14:33:30.223Z
The db error was that: https://throwbitcoins.blogspot.com/2018/11/exception-15dbwrappererror.html   Also no idea to fix it ;)
Pixxelcrasher
CC BY-SA 4.0
2019-08-06T18:33:29.987Z
I think this is an error caused a file blk corrupt, try to resincronize the bircoin core
vincenzopalazzo
CC BY-SA 4.0
2019-08-07T05:32:06.813Z
Now I got these: 2019-08-07T05:26:28Z ERROR: ReadBlockFromDisk: Deserialize or I/O error - ReadCompactSize(): size too large: iostream error at FlatFilePos(nFile=68, nPos=64215124)
2019-08-07T05:26:28Z *** Failed to read block
2019-08-07T05:26:28Z Error: A fatal internal error occurred, see debug.log for details
2019-08-07T05:26:28Z Failed to connect best block (Failed to read block (code 0))  Please Help
Pixxelcrasher
CC BY-SA 4.0
2019-08-07T08:02:17.890Z
The error persists, This line `ReadBlockFromDisk: Deserialize or I/O error - ReadCompactSize()` confirmed my thesis on the persistent file corrupt. Try to resynchronize directory with another location. Your file blk are downloaded with bitcoin core node or you downloaded it with another mode (an example torrent)
vincenzopalazzo
<bitcoin-core><blockchain><bitcoind>
Error after reindex
Pixxelcrasher
# Error after reindex

(Asked by: username_0 on 2019-08-06)

Hello after I got an db error.. I try to reindex my db. But I got this error:

ERROR: ReadBlockFromDisk: Errors in block header at FlatFilePos(nFile=75, nPos=117947311)

So what can I do to fix it ?

System:
4 cores
2 GB RAM
500GB ISCI Storage

**Tags:** bitcoin-core, blockchain, bitcoind

> **Comments:**
> **username_0**: The db error was that: https://throwbitcoins.blogspot.com/2018/11/exception-15dbwrappererror.html   Also no idea to fix it ;)  
> **username_1**: I think this is an error caused a file blk corrupt, try to resincronize the bircoin core  
> **username_0**: Now I got these: 2019-08-07T05:26:28Z ERROR: ReadBlockFromDisk: Deserialize or I/O error - ReadCompactSize(): size too large: iostream error at FlatFilePos(nFile=68, nPos=64215124) 2019-08-07T05:26:28Z *** Failed to read block 2019-08-07T05:26:28Z Error: A fatal internal error occurred, see debug.log for details 2019-08-07T05:26:28Z Failed to connect best block (Failed to read block (code 0))  Please Help  
> **username_1**: The error persists, This line `ReadBlockFromDisk: Deserialize or I/O error - ReadCompactSize()` confirmed my thesis on the persistent file corrupt. Try to resynchronize directory with another location. Your file blk are downloaded with bitcoin core node or you downloaded it with another mode (an example torrent)  

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## 1 answers

### Answer by username_2 on 2019-08-09. Score: 3

Your blockchain is corrupted. In Bitcoin Core's datadir, go to the blocks folder. Delete the file named `blk0075.dat` and ever `blk*.dat` file with a higher number. Also delete `rev0075.dat` and every `rev*.dat` file with a higher number. Start Bitcoin Core, it will need to reindex. At this point, it should begin building the block databases, and it will then download the blocks that you deleted once it gets to that point.

> **Comments:**
> **username_3**: If he deletes block files corresponding to already active blocks, he'll need a reindex from scratch anyway.  
> **username_4**: Why is it necessary to delete the following files? I have this error on my first file after moving them from SSD to HDD. However, I have the error at height 255, not at height 0. So part of the first file seems correct. I thought I just move this one file from another backup I have and it could work without reloading all the others.  
> **username_2**: Deleting the files is necessary if one or more blocks stored in the files are corrupted. Either your backup is corrupted, or the file was corrupted in transit. Typically there isn't any need to delete anything or to reindex.  

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