I installed Bitcoin QT yesterday and it was very slow to connect to the network. It didn't actually get there for over an hour.

Today I opened it again and it won't connect to the network at all. Any ideas why?

I'm running a Macbook Air with all software updated.

  • 1
    It would be useful if you could elaborate on exactly what Bitcoin QT seems to be doing - does it have any indication it's downloading the blockchain? From memory, as it does that it has a progress bar labelled with something like "Synchronizing..." Dec 13, 2011 at 21:26
  • I have the same issue, but it isn't a matter of verifying the block chain. I had it fully verified and up and running, and then one day, 0 connections. I can't connect to the network at all, so for me, the problem isn't a matter of waiting for the block chain to update. I just can't find the network. I'm running Windows XP. Any suggestions?
    – Adam
    Jul 19, 2013 at 14:14

3 Answers 3


You should get the best results if you port forward port 8333 to your laptop. It is also advised to leave your computer on for a long time the first time you connect to the network, as it has about 1GB of data to download and check. After that the operation should be easier.

  • Why does forwarding port 8333 provide best results? What if your tethering?
    – Liam W
    Feb 16, 2012 at 19:39
  • Bitcoin uses port 8333 for listening to other clients. Normally routers block such incoming transmissions, unless they are told to forward them to a specific computer. Basically, it allows your client to connect to more clients than without forwarding. Don't know much about tethering, but the situation might be similar.
    – ThePiachu
    Feb 16, 2012 at 22:36

You can download the blockchain and hence skip this long lasting initialization step.


You are probably still not synchronized to the network. When the client first starts up, it doesn't trust anything or anyone. So it has to validate every single thing the Bitcoin network has ever done in order to understand what coins are valid now. This can take 12 hours or so, depending on your connection speed and CPU speed.

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