qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.

aurelien

I know it is considered as a good software to build good software, but the point is here:

When you follow an installation guide step by step and make everything correctly, and the stuff does not works, that just mean it have been made with foot (from the stuff to the documentation.)

Really for thus who do their best, but it just not works on Debian 10 without doing weird things that should not be done out of the installation documentation.

Good luck

Obed

@Srinivas-Reddy Thanks. That helped me

Megan S

Thanks for all the helpful info on the thread!!

I am attempting an anaconda environment creation... I don't have admin privileges on the system I'm working on. It's Ubuntu16.04.1 LTS (Xenial Xerus)"

The error I get is below. I'm assuming that because I'm using the anaconda install vs using apt-get, I can't just easily reinstall? It looks to me as if I'm missing the libxcb-xinerama.so.0 package. I checked qmake --version, the output shows Qt version 5.9.7

Thanks for any suggestions!

QLibraryPrivate::loadPlugin failed on "/export/research/analysis/human/jstephen/shared/programs/python/anaconda_072020/new/envs/mne21/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqxcb.so" : "Cannot load library /export/research/analysis/human/jstephen/shared/programs/python/anaconda_072020/new/envs/mne21/lib/python3.8/site-packages/PyQt5/Qt/plugins/platforms/libqxcb.so: (libxcb-xinerama.so.0: cannot open shared object file: No such file or directory)"
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

$ qmake --version
QMake version 3.1
Using Qt version 5.9.7 in /export/research/analysis/human/jstephen/shared/programs/python/anaconda_072020/new/envs/mne21/lib

jsulm

@Megan-S said in qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.:

libxcb-xinerama.so.0: cannot open shared object file: No such file or directory

So do you have libxcb-xinerama.so.0?

mathsbloke

@Srinivas-Reddy Many thanks, that got mine working too!

C0K01

@Srinivas-Reddy Many thanks!

Jimit Rupani

@Advig said in qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.:

export QT_DEBUG_PLUGINS=1
export PATH=$PATH:~/Qt/Tools/QtCreator/bin
libxcb dependency so https://unix.stackexchange.com/questions/338519/how-to-install-libxcb gave the solution.

sudo apt-get install libxcb-randr0-dev libxcb-xtest0-dev libxcb-xinerama0-dev libxcb-shape0-dev libxcb-xkb-dev

sudo apt-get install libxkbcommon-x11-dev

solved my problem for ubuntu 20.04. Tried reinstalling almost 3 times before the solution. Hope it helps someone

coffeesmoke

So, Debian 10:

ldd -r <for example, home dir>/Qt/Tools/QtCreator/lib/Qt/plugins/platforms/libqxcb.so | grep libxcb-util

libxcb-util.so.1 => not found

Ok, continue...
sudo find /usr/lib | grep libxcb-util
...
libxcb-util.so.0.0.0
libxcb-util.so.0.0
libxcb-util.so.0
, but need
libxcb-util.so.1
Ok, Debian... :) Redy?
sudo ln -fs /usr/lib/x86_64-linux-gnu/libxcb-util.so.0.0.0 /usr/lib/x86_64-linux-gnu/libxcb-util.so.1.0.0
sudo ln -fs /usr/lib/x86_64-linux-gnu/libxcb-util.so.0.0.0 /usr/lib/x86_64-linux-gnu/libxcb-util.so.1.0
sudo ln -fs /usr/lib/x86_64-linux-gnu/libxcb-util.so.0.0.0 /usr/lib/x86_64-linux-gnu/libxcb-util.so.1

QtCreator start complete! :))))

stounhange7

@coffeesmoke thanks for the help. you revived my qt on debian 10

1init

@coffeesmoke thank you for this i ran the debian 9 instructions after installing the updates and had this issue
i run devuan

Malachi

That symlink seems a little risky. Two worries:

What happens when the actual v1+ of the actual libxcb-util attempts to install?
Are you 100% sure Qt Creator isn't depending on a different API? Seems like a dice roll

I admit though, it's better than nothing

EDIT: A few minutes of browsing https://gitlab.freedesktop.org/xorg/lib/libxcb-util/-/blob/master/NEWS suggests that no API changes are there and that symlinking is probably API compliant in this case. Funny that Debian is 6 years behind on this lib. No judging. I know they gotta test stuff. Just funny :)

SlySven

Assuming that version 0 of something is a pre-first version release and that Devuan 3.0 "Beowulf" (systemd-less fork of Debian 10.0 "Buster") only has the 0.0.0 version then I guess symlinking the 0.0.0 to the 1.0.0 is the only chance we've got. I just got clobbered by this when running the Qt Creator updater from within the last version that was giving me Qt 5.15.1 that told me that there was an update available. It is a real PITA when it upgraded itself out of working...

... however this topic has worked for me.

BTW The Devuan libxcb-util 0.0.0 version libraries do date back to 20 Aug 2014!

beetree

@coffeesmoke

As for Debian. The correct library is found as of Debian 11. Which at the moment is in testing.

Qt application fails to start on Debian 10 Buster because libqxcb.so requires missing libxcb-util.so.1

Symlink to a different library version is a possible workaround, but does not guarantee everything else works as expected, and as such ill advised.

saulesquivelg

I had the same problem after installing QT in Ubuntu 18.04, I've solved it with sudo apt install libxcp-xinerama0

coffeesmoke

@beetree I agree. Alternatively , a virtual machine. But if you do not want to install the VM, you need to save the changes in the notations to yourself to be able to return to the original version.

Alexreell

@Jimit-Rupani Thank you, the first 2 points on kali linux helped me

Niffo

@coffeesmoke Thank you VERY much !

sheril

@Srinivas-Reddy
Thanks.

requinham

@Lengendary Thanks, this resolve the problem for me on Ubuntu 18.04 Qt 5.15.2

CoreDump

Environment: Ubuntu20.10; Qt 5.15.2, VirtualBox VM:

The solution provided by @Legendary no longer works, use this instead:

$ sudo apt-get install libxcb-randr0-dev libxcb-xtest0-dev libxcb-xinerama0-dev libxcb-shape0-dev libxcb-xkb-dev