Peercoin v0.6.1 Now Released, Upgrade Today! Blockchain Redownload Required! (Instructions Inside)

Peercoin v0.6.1 Released, Upgrade Today!

Hey guys, after a long wait, Peercoin v0.6 is finally here. This is the first release from Peercoin’s new team, which marks the transition away from Peercoin being developed solely by its founder Sunny King. This upgrade will require a full blockchain redownload due to the move to the leveldb database.

Installation Instructions…

Installation instructions and a summary of what has changed in this version are provided in the following Medium article. Peerunity is no longer being supported, and the article below explains the upgrade process…


You can post in this thread in case you have questions or bugs to report. Please help retweet this news for us here…


First of all, make sure to have backups of your wallet.dat file!

My client crashes on initial blockchain download.

The following error is shown in debug.log: ERROR: mempool transaction missing input
This is a known issue caused by syncing with a not-encrypted wallet.dat file.
There are multiple options to avoid this:

  • Run the initial blockchain download without wallet.dat file (move it outside the datadir)
    After full download, stop the client, copy your wallet.dat back in place and restart.
  • Run the initial download with minting disabled (v0.6.1 feature)
    add nominting=1 to your peercoin.conf file or use the -nominting commandline parameter.
    To turn it back on after full download, remove the option and restart the client.

My client fully synced but my balances are wrong

This can happen due to inconsistencies between the wallet.dat file and the block DB.
Since v0.6.1 the zapwallettxes feature has been backported from bitcoin. This option clears your wallet.dat file except for the private keys and fully rescans the chain for wallet transactions to compute your balance.

  • Start your client with zapwallettxes=1 in peercoin.conf or with -zapwallettxes on the commandline. Make sure to remove the option after startup otherwise it’ll repeat the process every time you start the client, it doesn’t hurt but it takes a while.
    Note: You don’t need to re-download the blockchain for this.

Ultimate recovery, in case none of the above helps

  • Open your wallet.dat with the client that is able to open it and read the addresses stored in it (it doesn’t matter if balances are displayed correctly)
  • In the debug window or RPC console, export all the private keys for every address that contains coins using:
    dumpprivkey <your_address>
  • Store these keys safely, anyone with access to those can spend your coins.
  • Start the latest peercoin client without wallet.dat file, it will create an empty one.
  • When fully synced, import your private keys one by one in the debug window or RPC console using:
    importprivkey <your_private_key>

Announcement also posted on r/cryptocurrency here…


It was brought up on Bitcointalk that someone saw v0.4.0ppc-2108-gbcd7712 (V0.4.0) under About Peercoin. This is a known issue and the developers have said it will be fixed properly in a post release, v0.6.1.

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Upgrade went very smoothly… Well done PPC Devs


I like the new core client. Very sleek.

Shame we need to re-download the bockchain…

The blockchain is still under 1 Gb, so it shouldn’t take too long.


Congratulations on the v0.6 release! Impressive job from the Peercoin development team!

恭贺 0.6 版发布!祝 Peercoin团队 再接再厉,更上层楼!


So started off promising but windows client is hanging and crashing for me. Is there any bug reports/diagnostics or other information I can pass back to the dev team?

It seemed to be caused by allowing minting (unlocking the wallet for minting only) whilst the blockchain was still downloading.

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I believe there should be a file in your Peercoin folder called debug.log.

ok this is in the log just before the crash;

017-11-01 23:32:41 ERROR: mempool transaction missing input
2017-11-01 23:32:41 ERROR: mempool transaction missing input
2017-11-01 23:32:41 ERROR: mempool transaction missing input
2017-11-01 23:32:41 ERROR: mempool transaction missing input
2017-11-01 23:32:41 ERROR: mempool transaction missing input
2017-11-01 23:32:41 ERROR: mempool transaction missing input
2017-11-02 02:08:40

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This seems to have been reported here as well…

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@Zangy Can you try downloading the chain with an empty wallet.dat file (just move it somewhere else).
You can put the wallet.dat file back after download.

Can you try if that fixes your issue?

The wallet.dat that you used during the crashes, I guess it was not encrypted using walletlock?
(During our tests we used encrypted wallets)

In next point release (0.6.1) we’ll fix this problem, basically we’ll disable minting while wallet is syncing. That’s what causing this problem.


I’ll add a note about this in the first post.

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I think the linux sha256 is wrong on

On there is the hash 177755712890bec1dc28213df2fb65b7e68c6f686ce10ad796fb7d280778ebc4
To me the 256 sha gives me a21f5ca1c9a5b0cc48da98888dfc376d55e4338ca1484ee701e049077976fd50

Thanks, we’ve let our webmaster know to fix it.

Sorry @hrobeers just got back from work. Still want me to try with a standard wallet.dat file or is this now superceded given peerchemist’ diagnosis…?

If your blockchain is now fully synced then it doesn’t matter anymore. The reason I believe hrobeers was asking you to use an empty wallet is because an empty wallet has no possibility of minting a block. As long as your wallet was not trying to mint while syncing, there should be no issue. However if your chain is fully synced then there is no way to test it unless you delete and redownload again.

Also, just in case you didn’t know, if you have a wallet with peercoins in it and it is unencrypted, then minting starts automatically. If the wallet is encrypted though, then it will not mint automatically and the only way is to hit “unlock wallet for minting only.”

Thanks, my wallet was encrypted and had peercoins in it. I did manually unlock it for minting during the blockchain sync which seems to cause the crashes so that is consistent with the findings from the dev team above. I’m happy to delete and re-test if that helps anyone, not a problem

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