I've tried syncing this same MacBook Pro multiple times and it keeps stalling. The debug.log file keeps repeating the same two lines at block 275162:

2017-07-07 03:09:59 ERROR: ConnectBlock: Consensus::CheckBlock: bad-txnmrklroot, hashMerkleRoot mismatch (code 16) 2017-07-07 03:09:59 ERROR: ConnectTip(): ConnectBlock 0000000000000002373cc5cc98604fa31361a495ec20eebb54861e9f489d3336 failed

Any light on the issue would be appreciated.

1 Answer 1


This error means that you have a corrupted block. The only surefire way to fix this is to redownload the entire blockchain. You can do that by going to the Bitcoin Core datadir (get the path by going to Help > Debug Window in Core and there will be a field labeled datadir) and deleting the blocks folder, after first shutting down Core. Then start Core and let it sync from scratch.

  • Thanks for your reply. I have already deleted the blocks directory previously as it stalled before. This has happened several times now syncing from scratch. Would this be a hardware issue at this point? I can sync on other machines just fine. Jul 7, 2017 at 14:12
  • 1
    If you are consistently seeing the same error, then you likely have a hardware issue. In that case, you should run hardware diagnostics to see if any errors are detected. The things to check for are the memory and the disk.
    – Andrew Chow
    Jul 7, 2017 at 16:37

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