Cannot mix incompatible Qt library

[Mohamed IKBEL Boulabiar]

After an habitual system update, some Qt packages are updated to 4.8.4 and other stayed at 4.8.3
Many Qt apps no more work on my x64 install

$ qdbusviewer
Cannot mix incompatible Qt library (version 0x40803) with this library (version 0x40804)
Aborted (core dumped)

Then to make it work, I need to do this before launching the app
$ export LD_LIBRARY_PATH=/usr/lib/x86_64-linux-gnu/

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: libqt4-core (not installed)
ProcVersionSignature: Ubuntu 3.5.0-26.42-generic 3.5.7.6
Uname: Linux 3.5.0-26-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.6.1-0ubuntu10
Architecture: amd64
Date: Mon Apr 8 11:38:53 2013
InstallationDate: Installed on 2012-01-12 (451 days ago)
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
MarkForUpload: True
SourcePackage: qt4-x11
UpgradeStatus: Upgraded to quantal on 2012-11-27 (131 days ago)

[elguavas (elguavas.)]

i'm also now getting this problem on a 13.04 system since todays updates which included some qt libraries...

Cannot mix incompatible Qt library (version 0x40804) with this library (version 0x40803)
Aborted (core dumped)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Jun Inoue (jun-lambda)]

I'm affected by this as well. When I try to start any of okular, VirtualBox (the qt GUI), kmail, or AFAICT anything that uses qt4, I get

$ kmail
Cannot mix incompatible Qt library (version 0x40804) with this library (version 0x40801)
zsh: abort (core dumped) kmail

$ okular
Cannot mix incompatible Qt library (version 0x40804) with this library (version 0x40801)
KCrash: Application 'okular' crashing...
KCrash: Attempting to start /usr/lib/kde4/libexec/drkonqi from kdeinit
sock_file=/home/jun/.kde/socket-jun-MacBookAir/kdeinit4__0
Warning: connect() failed: : No such file or directory
KCrash: Attempting to start /usr/lib/kde4/libexec/drkonqi directly
Cannot mix incompatible Qt library (version 0x40804) with this library (version 0x40801)

$ anki
Cannot mix incompatible Qt library (version 0x40804) with this library (version 0x40801)
zsh: abort (core dumped) anki

I've tried recompiling okular from the source package, but I got the same exact error. This has rendered many packages completely unusable for me. I think this bug deserves a high importance rating, unless it's rare (i.e. affecting few people), because AFAICT for those who are affected this bug is seriously crippling.

[SA (superaorta)]

I appear to have this (or similar) with openscad on Ubuntu 14.04.1 LTS

>> openscad
Cannot mix incompatible Qt library (version 0x40806) with this library (version 0x40804)
Abort (core dumped)

[Rohan Garg (rohangarg)]

Hi
Could you possibly pastebin the output of apt-cache policy libqt4-opengl

[Patrick Hervieux (hervieuxpatrick)]

I have the same problem like SA.
This is the output of apt-cache policy libqt4-opengl:
libqt4-opengl:
  Installé : 4:4.8.5+git192-g085f851+dfsg-2ubuntu4
  Candidat : 4:4.8.5+git192-g085f851+dfsg-2ubuntu4
 Table de version :
 *** 4:4.8.5+git192-g085f851+dfsg-2ubuntu4 0
        500 http://ch.archive.ubuntu.com/ubuntu/ trusty/main i386 Packages
        100 /var/lib/dpkg/status
I'm using Ubuntu 14.04 LTS i686 and actually I have only problem with OpenScad.

[SA (superaorta)]

apt-cache policy libqt4-opengl
libqt4-opengl:
  Installed: 4:4.8.5+git192-g085f851+dfsg-2ubuntu4.1
  Candidate: 4:4.8.5+git192-g085f851+dfsg-2ubuntu4.1
  Version table:
 *** 4:4.8.5+git192-g085f851+dfsg-2ubuntu4.1 0
        500 http://gb.archive.ubuntu.com/ubuntu/ trusty-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu/ trusty-security/main amd64 Packages
        100 /var/lib/dpkg/status
     4:4.8.5+git192-g085f851+dfsg-2ubuntu4 0
        500 http://gb.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages

[SA (superaorta)]

FWIW installing the tarball compiled openscad from the openscad home was painless and works fine...

[SA (superaorta)]

Scratch that last comment the tarball runs fine at first and then crashes with the same incompatible QT error as before.

However building openscad from source (openscad-2015.03-1) results in a working version - building takes ~20minutes and by way of compensation the new version is nicer.