[Solved] Reddcoin 3.10.3 core crashes: !"cannot load block from disk"

My Reddcoin wallet worked fine for years, running 24x7 to keep staking. Now on v3.10.3.0-00eedb8-beta (64-bit). But last weeks it keeps crashing:

Assertion failed!
File: main.cpp, Line 3837
Expression: !“cannot load block from disk”

I already rebuilt with the bootstrap files, but now always a few hours after starting up the app crashes with this error message.

Any clues how to fix this?

First time I’m seeing that error. Reading the error and searching some on the internet, I think the issue might be related to your hard drive.

I would recommend to check the health of your drive.

You can use CrystalDiskInfo, for example.
A portable version (works without installing): https://portableapps.com/apps/utilities/crystaldiskinfo_portable.

Can you run that software and post a screenshot of the results?

Thank you, here the screenshot. Looks good i guess. Also my ‘Hard Disk Sentinel Pro’ utility does not signal any errors.

Is your blockchain data saved on D: or E:?

By default, it’s stored on C:.

Can you also post a screenshot of C:?

Program and data all on D:


You already have deleted existing blockchain data and bootstrapped. That’s what I would do as well. That doesn’t seem to have fixed the issue…

In your case, I would try the following myself:

  • Exit/close Reddcoin Core, make sure it’s not running.
  • Copy the current Reddcoin data directory to another partition on another drive. In your case, I would go for F: or G:.
  • Start Reddcoin Core with -choosedatadir, and use the new location (on F: or G:).

Then, I would monitor if Reddcoin Core still gives an error.
If there is no error, the disk would seem to be the issue.
If it does give an erorr, I will ask you about how you have done the bootstrapping, to make sure you haven’t missed anything.

Ok, will try. Reddcoin data and Redcoin core are in 1 directory on D. Can I copy the whole folder to another drive then? Do I still have to use -choosdatadir?

Or should I only move the /blocks and /chainstate folders to another disk and restart with -choosedatadir?

I can give you the exact instructions, but I need to know if we talk about the same thing.

  • Reddcoin installation/program directory:
    Contains the wallet software - Reddcoin Core.

  • Reddcoin data directory:
    Contains the blockchain data and your wallet file, and other necessary files.


Can you post the location of these 2 directories? And a screenshot of the content (so I can see/verify it’s the correct folder).


  • Don’t move anything, but copy.
  • You only need to copy your Reddcoin data directory (contains your blockchain folders).
  • You need to start with -choosedatadir to make sure Reddcoin Core uses the new location.

I will tell you exactly how to the steps, but first I need to know the locations.

All is in 1 directory on D:

Okay, current location is: D:\Reddcoin.

  • Copy the Reddcoin folder on D: to F:.

  • So, the new location is: F:\Reddcoin.

  • Start Reddcoin Core with the -choosedatadit parameter/argument.

    • Press Windows key + R.
      The ‘Run’ window should open.
      In Run, enter this (copy/paste):
      "F:\Reddcoin\reddcoin-qt.exe" -choosedatadir
  • Reddcoin Core will start (from the new location). It will ask you for the data directory.
    → Select F:\Reddcoin as your data directory.


Check if this solves your issue…

I chose H, a healthy SSD drive…:slight_smile:

Done, up and running now, will let you know, thanks a lot!

And? Had any issues since running Reddcoin Core on H:?

Hi! All running fine now on H! I guess you were right about the disk. Very strange that 2 disk-checkers do not notice this :-(. Thanks for your help!.

I would recommend you to backup the data on the drive with possible issues.

Glad Reddcoin Core works without issues on H:.