Bitcoin QT doesn't synchronize with the blockchain

[Josepht]

Hi all,

I have some problems with the bitcoin core. I downloaded it yesterday. It started synchronizing without any problems.
I left it synchonizing overnight, and when I woke up, it was only 16 weeks behind.

Now (12 hours later), it is at the same point as it was when I woke up. I have 8 active connections to the network, and the programm says that it is synchronizing.

What do I have to do to make it working?

[shorena]

Hi all,

I have some problems with the bitcoin core. I downloaded it yesterday. It started synchronizing without any problems.
I left it synchonizing overnight, and when I woke up, it was only 16 weeks behind.

Now (12 hours later), it is at the same point as it was when I woke up. I have 8 active connections to the network, and the programm says that it is synchronizing.

What do I have to do to make it working?

Did you try turning it off and on again? Sometimes that helps.
Also check if you are actually downloading anything.

[Josepht]

Did you try turning it off and on again? Sometimes that helps.
Also check if you are actually downloading anything.

That's what I tried several times. It doesn't work.

As far as I can see, in the bottem left corner it says 'synchronizing with network'. I guess it is downloading?

[shorena]

Did you try turning it off and on again? Sometimes that helps.
Also check if you are actually downloading anything.

That's what I tried several times. It doesn't work.

As far as I can see, in the bottem left corner it says 'synchronizing with network'. I guess it is downloading?

Check Help -> Debug Window -> Network Traffic
There should be plenty of green. You can also check in the Information tab the current number of blocks and the estimated number of blocks

If you dont get any new blocks for several minutes try adding a node from this list https://en.bitcoin.it/wiki/Fallback_Nodes or this https://blockchain.info/connected-nodes
with

Code:

addnode ip/url add 

in the Console tab.

[Josepht]

Yes, there is quite a lot of green after I added a node.
Problem is that the current number of blocks isn't changing.

[zvs]

bitcoin-qt --maxconnections=1 --listen=0 --connect=5.9.24.81

if it doesn't sync then, start over

[Josepht]

Even after 24 hours, nothing has changed. It is still stuck at the same block.

Indeed, I do have a computer which is 4 years old, but I experienced no problems untill this block.

[shorena]

Even after 24 hours, nothing has changed. It is still stuck at the same block.

Indeed, I do have a computer which is 4 years old, but I experienced no problems untill this block.

Could it be another programm that is blocking access to the files? Antivirus software that detected a false positive in the blockchain would a likely candidate.

You might want to try the bootstrap.dat¹ and start from there.

[1] https://bitcoin.org/bin/blockchain/bootstrap.dat.torrent

[zvs]

do what i said earlier, but i guess maybe like this:

bitcoin-qt -reindex -maxconnections=1 -connect=5.9.24.81 -connect=5.9.24.81 -par=8

... or change par to the number of threads for your CPU... also, the reason for two connect='s is because i've found that a lot of times when i just use one connect=, it'll sometimes connect to some other node first, dunno what's up with that

[alexander.y.k]

I had same problem.
Out of sync for few hours, then ten, then 40... Restarts and walk through proxy doesn't help. Eight connections were present and adding another nodes from https://en.bitcoin.it/wiki/Fallback_Nodes has no effect, "Network Traffic" tab in Debug Window doesn't show any serious activity.
Then I check data directory and found debug.log. There was interesting moment:

...
2014-05-28 20:53:03 receive version message: /Satoshi:0.8.6/: version 70001, blocks=303083, us=xxx.xxx.xxx.xxx:123, them=yyy.yyy.yyy.yyy:8333, peer=0.0.0.0:0
2014-05-28 20:53:04 ERROR: Proxy error: connection refused
2014-05-28 20:53:04 SOCKS5 connecting seed.bitcoinstats.com
2014-05-28 20:53:05 CheckForkWarningConditions: Warning: Large valid fork found
  forking the chain at height 302787 (000000000000000063db9b526e9cbe0cec7053157df6ea0f0ee895addc355b26)
  lasting to height 303083 (0000000000000000378f60f49b076dc6de665a3fd6eba18313ded3c61df65737).
Chain state database corruption likely.
2014-05-28 20:53:05 ProcessBlock: ACCEPTED
...


So I close bitcoin-qt, rename blocks and chainstate directories (to make illusion for bitcoin-qt that we have no local copy of blockchain), download boostrap.dat in this directory and next start of bitcoin-qt synchronize from file and then from network without problems and still ok.

[alexander.y.k]

Need to say that I rename those directories again to reconstruct stuck state of bitcoin core. Then run bitcoin-qt -reindex and this resolve problem too. So this is much easier way.