I believe this occurred after I tried to change the name of my computer since it was a default and had a bunch of numbers after it.

After changing it, I started to experience weird things with my sudo command, such as my password failing multiple times. A reboot ended up fixing that.

Now I am trying to run my bitcoin-core using bitcoin-qt in the terminal.

It gives me this error:

bitcoin-qt: symbol lookup error: bitcoin-qt: undefined symbol: _ZN12QApplication10commitDataER15QSessionManager

I've tried to uninstall using --purge and reinstall. I've deleted the folder in /usr/bin/bitcoin-qt and tried running it from that folder itself but still wouldn't work.

I'm not sure if there is a config file somewhere else that it uses but I've tried just about everything short of a complete OS reinstallation and nothing will work.

I did change my hostname in /etc/hosts and /etc/hostname and even tried to change it back to what it originally was which was like "xxx-GL551JK" but my bitcoin core refuses to open.

I've tried running just the program itself too from the Search menu and that doesn't work either.

Edit 1: I just reinstalled a fresh copy of Ubuntu and the same error popped up. I literally had this thing running yesterday. I'm already pretty tired of Ubuntu. Almost nothing works out of box.

Edit 2: I just did a second reinstall while overwriting the entire SSD and installed it just the way I did the first time and it's all working again.

Edit 3: I've reinstalled this system I don't know how many times. Every time I reset my computer after downloading the Core, it gives me this lookup error. Literally have reinstalled 4 times and every time it occurs after restarting my computer. I've closed the application and even sudo killall bitcoin-qt every time I tried to log off and then it inevitably gives me this same symbol lookup error. I've even tried 2 different versions of Ubuntu.

  • Did you bother to find out how changing a hostname would affect your bitcoin app before doing so, and how long have you been using Ubuntu? – George Udosen Sep 27 '17 at 5:47
  • Why should changing my name on a computer that gives me a UI to change my name affect anything? It's like offering a button to blow up your system in a folder on the Desktop. – cchoe1 Sep 29 '17 at 16:41

I found the solution:

I'm on a 64 bit installation of Ubuntu 16.04.

I went to /usr/local/lib and found all my QtCore/QtGui/QtNetwork files there. I moved them all to /usr/.

Now I can run Bitcoin-qt again fine.

I have no idea why it breaks or why it cannot seem to run after the initial boot up or why this fixes it but it seems to work.

Note: There are many libQtCore/Gui/Network files for many different programs but it seems Bitcoin-qt uses the ones in /usr/local/lib and it breaks for some reason whenever you restart the computer. Moving them fixed it for me but only moving the ones in /usr/local/lib and all of them.

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