qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found. (2024)

@Lengendary Thank you!

Hey guys,

I'm getting the same error but not able to find any reason.
I'm building this project, https://github.com/BelledonneCommunications/linphone-desktop
and getting the error,

(linphone) ➜ Packages git:(master) ./Linphone-4.5.1.AppImage 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.Available platform plugins are: xcb.[1] 28317 abort (core dumped) ./Linphone-4.5.1.AppImage(linphone) ➜ Packages git:(master) ldd ~/Qt/5.12.9/gcc_64/plugins/platforms/libqxcb.so linux-vdso.so.1 (0x00007ffe12cd8000)libQt5XcbQpa.so.5 => /home/ravi/Qt/5.12.9/gcc_64/plugins/platforms/../../lib/libQt5XcbQpa.so.5 (0x00007f79c2a18000)libfontconfig.so.1 => /usr/lib/x86_64-linux-gnu/libfontconfig.so.1 (0x00007f79c27d3000)libfreetype.so.6 => /usr/lib/x86_64-linux-gnu/libfreetype.so.6 (0x00007f79c251f000)libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007f79c2302000)libQt5Gui.so.5 => /home/ravi/Qt/5.12.9/gcc_64/plugins/platforms/../../lib/libQt5Gui.so.5 (0x00007f79c1ab3000)libQt5DBus.so.5 => /home/ravi/Qt/5.12.9/gcc_64/plugins/platforms/../../lib/libQt5DBus.so.5 (0x00007f79c1827000)libQt5Core.so.5 => /home/ravi/Qt/5.12.9/gcc_64/plugins/platforms/../../lib/libQt5Core.so.5 (0x00007f79c108c000)libGL.so.1 => /usr/lib/x86_64-linux-gnu/libGL.so.1 (0x00007f79c0e00000)libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f79c0be1000)libX11-xcb.so.1 => /usr/lib/x86_64-linux-gnu/libX11-xcb.so.1 (0x00007f79c09df000)libxcb.so.1 => /usr/lib/x86_64-linux-gnu/libxcb.so.1 (0x00007f79c07b7000)libXrender.so.1 => /usr/lib/x86_64-linux-gnu/libXrender.so.1 (0x00007f79c05ad000)libXext.so.6 => /usr/lib/x86_64-linux-gnu/libXext.so.6 (0x00007f79c039b000)libX11.so.6 => /usr/lib/x86_64-linux-gnu/libX11.so.6 (0x00007f79c0063000)libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f79bfcc5000)libxkbcommon-x11.so.0 => /usr/lib/x86_64-linux-gnu/libxkbcommon-x11.so.0 (0x00007f79bfabd000)libxkbcommon.so.0 => /usr/lib/x86_64-linux-gnu/libxkbcommon.so.0 (0x00007f79bf87e000)libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f79bf67a000)libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007f79bf2f1000)libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f79bf0d9000)libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f79bece8000)libgthread-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libgthread-2.0.so.0 (0x00007f79beae6000)libglib-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0 (0x00007f79be7cf000)libexpat.so.1 => /lib/x86_64-linux-gnu/libexpat.so.1 (0x00007f79be59d000)libpng16.so.16 => /usr/lib/x86_64-linux-gnu/libpng16.so.16 (0x00007f79be36b000)libdbus-1.so.3 => /lib/x86_64-linux-gnu/libdbus-1.so.3 (0x00007f79be11e000)libicui18n.so.56 => /home/ravi/Qt/5.12.9/gcc_64/plugins/platforms/../../lib/libicui18n.so.56 (0x00007f79bdc85000)libicuuc.so.56 => /home/ravi/Qt/5.12.9/gcc_64/plugins/platforms/../../lib/libicuuc.so.56 (0x00007f79bd8cd000)libicudata.so.56 => /home/ravi/Qt/5.12.9/gcc_64/plugins/platforms/../../lib/libicudata.so.56 (0x00007f79bbeea000)/lib64/ld-linux-x86-64.so.2 (0x00007f79c2fbe000)libGLX.so.0 => /usr/lib/x86_64-linux-gnu/libGLX.so.0 (0x00007f79bbcb9000)libGLdispatch.so.0 => /usr/lib/x86_64-linux-gnu/libGLdispatch.so.0 (0x00007f79bba03000)libXau.so.6 => /usr/lib/x86_64-linux-gnu/libXau.so.6 (0x00007f79bb7ff000)libXdmcp.so.6 => /usr/lib/x86_64-linux-gnu/libXdmcp.so.6 (0x00007f79bb5f9000)libxcb-xkb.so.1 => /usr/lib/x86_64-linux-gnu/libxcb-xkb.so.1 (0x00007f79bb3dd000)libpcre.so.3 => /lib/x86_64-linux-gnu/libpcre.so.3 (0x00007f79bb16b000)libsystemd.so.0 => /lib/x86_64-linux-gnu/libsystemd.so.0 (0x00007f79baee7000)libbsd.so.0 => /lib/x86_64-linux-gnu/libbsd.so.0 (0x00007f79bacd2000)librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007f79baaca000)liblzma.so.5 => /lib/x86_64-linux-gnu/liblzma.so.5 (0x00007f79ba8a4000)liblz4.so.1 => /usr/lib/x86_64-linux-gnu/liblz4.so.1 (0x00007f79ba688000)libgcrypt.so.20 => /lib/x86_64-linux-gnu/libgcrypt.so.20 (0x00007f79ba36c000)libgpg-error.so.0 => /lib/x86_64-linux-gnu/libgpg-error.so.0 (0x00007f79ba157000)

What could be the issue? Please suggest.
Please let me know if you need to know anything else for this.

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

Hey guys,

I'm getting the same error but not able to find any reason.
I'm building this project, https://github.com/BelledonneCommunications/linphone-desktop
and getting the error,

(linphone) ➜ Packages git:(master) ./Linphone-4.5.1.AppImage 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.Available platform plugins are: xcb.[1] 28317 abort (core dumped) ./Linphone-4.5.1.AppImage(linphone) ➜ Packages git:(master) ldd ~/Qt/5.12.9/gcc_64/plugins/platforms/libqxcb.so linux-vdso.so.1 (0x00007ffe12cd8000)libQt5XcbQpa.so.5 => /home/ravi/Qt/5.12.9/gcc_64/plugins/platforms/../../lib/libQt5XcbQpa.so.5 (0x00007f79c2a18000)libfontconfig.so.1 => /usr/lib/x86_64-linux-gnu/libfontconfig.so.1 (0x00007f79c27d3000)libfreetype.so.6 => /usr/lib/x86_64-linux-gnu/libfreetype.so.6 (0x00007f79c251f000)libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007f79c2302000)libQt5Gui.so.5 => /home/ravi/Qt/5.12.9/gcc_64/plugins/platforms/../../lib/libQt5Gui.so.5 (0x00007f79c1ab3000)libQt5DBus.so.5 => /home/ravi/Qt/5.12.9/gcc_64/plugins/platforms/../../lib/libQt5DBus.so.5 (0x00007f79c1827000)libQt5Core.so.5 => /home/ravi/Qt/5.12.9/gcc_64/plugins/platforms/../../lib/libQt5Core.so.5 (0x00007f79c108c000)libGL.so.1 => /usr/lib/x86_64-linux-gnu/libGL.so.1 (0x00007f79c0e00000)libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f79c0be1000)libX11-xcb.so.1 => /usr/lib/x86_64-linux-gnu/libX11-xcb.so.1 (0x00007f79c09df000)libxcb.so.1 => /usr/lib/x86_64-linux-gnu/libxcb.so.1 (0x00007f79c07b7000)libXrender.so.1 => /usr/lib/x86_64-linux-gnu/libXrender.so.1 (0x00007f79c05ad000)libXext.so.6 => /usr/lib/x86_64-linux-gnu/libXext.so.6 (0x00007f79c039b000)libX11.so.6 => /usr/lib/x86_64-linux-gnu/libX11.so.6 (0x00007f79c0063000)libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f79bfcc5000)libxkbcommon-x11.so.0 => /usr/lib/x86_64-linux-gnu/libxkbcommon-x11.so.0 (0x00007f79bfabd000)libxkbcommon.so.0 => /usr/lib/x86_64-linux-gnu/libxkbcommon.so.0 (0x00007f79bf87e000)libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f79bf67a000)libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007f79bf2f1000)libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f79bf0d9000)libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f79bece8000)libgthread-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libgthread-2.0.so.0 (0x00007f79beae6000)libglib-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0 (0x00007f79be7cf000)libexpat.so.1 => /lib/x86_64-linux-gnu/libexpat.so.1 (0x00007f79be59d000)libpng16.so.16 => /usr/lib/x86_64-linux-gnu/libpng16.so.16 (0x00007f79be36b000)libdbus-1.so.3 => /lib/x86_64-linux-gnu/libdbus-1.so.3 (0x00007f79be11e000)libicui18n.so.56 => /home/ravi/Qt/5.12.9/gcc_64/plugins/platforms/../../lib/libicui18n.so.56 (0x00007f79bdc85000)libicuuc.so.56 => /home/ravi/Qt/5.12.9/gcc_64/plugins/platforms/../../lib/libicuuc.so.56 (0x00007f79bd8cd000)libicudata.so.56 => /home/ravi/Qt/5.12.9/gcc_64/plugins/platforms/../../lib/libicudata.so.56 (0x00007f79bbeea000)/lib64/ld-linux-x86-64.so.2 (0x00007f79c2fbe000)libGLX.so.0 => /usr/lib/x86_64-linux-gnu/libGLX.so.0 (0x00007f79bbcb9000)libGLdispatch.so.0 => /usr/lib/x86_64-linux-gnu/libGLdispatch.so.0 (0x00007f79bba03000)libXau.so.6 => /usr/lib/x86_64-linux-gnu/libXau.so.6 (0x00007f79bb7ff000)libXdmcp.so.6 => /usr/lib/x86_64-linux-gnu/libXdmcp.so.6 (0x00007f79bb5f9000)libxcb-xkb.so.1 => /usr/lib/x86_64-linux-gnu/libxcb-xkb.so.1 (0x00007f79bb3dd000)libpcre.so.3 => /lib/x86_64-linux-gnu/libpcre.so.3 (0x00007f79bb16b000)libsystemd.so.0 => /lib/x86_64-linux-gnu/libsystemd.so.0 (0x00007f79baee7000)libbsd.so.0 => /lib/x86_64-linux-gnu/libbsd.so.0 (0x00007f79bacd2000)librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007f79baaca000)liblzma.so.5 => /lib/x86_64-linux-gnu/liblzma.so.5 (0x00007f79ba8a4000)liblz4.so.1 => /usr/lib/x86_64-linux-gnu/liblz4.so.1 (0x00007f79ba688000)libgcrypt.so.20 => /lib/x86_64-linux-gnu/libgcrypt.so.20 (0x00007f79ba36c000)libgpg-error.so.0 => /lib/x86_64-linux-gnu/libgpg-error.so.0 (0x00007f79ba157000)

What could be the issue? Please suggest.
Please let me know if you need to know anything else for this.

Hey @SGaist , Can you please suggest anything for this?

@singhravi run ldd on the plugin itself.

I missed that line.

I see that you have that issue with an AppImage, does it also happen with just your binary ?

@SGaist
I'm building this project from github, https://github.com/BelledonneCommunications/linphone-desktop.
It has the everything included in its cmakelists.txt and I just need to add -DENABLE_APP_PACKAGING=YES to create the package.
It uses linuxdeploy and linuxdeploy-plugin-qt for packaging.
This is the script for packaging, https://github.com/BelledonneCommunications/linphone-desktop/blob/master/linphone-app/tools/create_appimage.sh

@SGaist
I'm building this project from github, https://github.com/BelledonneCommunications/linphone-desktop.
It has the everything included in its cmakelists.txt and I just need to add -DENABLE_APP_PACKAGING=YES to create the package.
It uses linuxdeploy and linuxdeploy-plugin-qt for packaging.
This is the script for packaging, https://github.com/BelledonneCommunications/linphone-desktop/blob/master/linphone-app/tools/create_appimage.sh

Hey @SGaist , Please let me know if you need anyother information.

One thing I noted while running the Appimage with QT_DEBUG_PLUGINS=1 was that it was trying to load plugins from a directory in tmp directory which does not exists. I don't know if this is the correct behaviour.
Following the log when i run the Appimage,

QFactoryLoader::QFactoryLoader() checking directory path "/tmp/.mount_LinphoELXhn2/usr/plugins/platforms" ...QFactoryLoader::QFactoryLoader() looking at "/tmp/.mount_LinphoELXhn2/usr/plugins/platforms/libqxcb.so"Found metadata in lib /tmp/.mount_LinphoELXhn2/usr/plugins/platforms/libqxcb.so, metadata={ "IID": "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3", "MetaData": { "Keys": [ "xcb" ] }, "className": "QXcbIntegrationPlugin", "debug": false, "version": 329989}Got keys from plugin meta data ("xcb")QFactoryLoader::QFactoryLoader() checking directory path "/tmp/.mount_LinphoELXhn2/usr/bin/platforms" ...Cannot load library /tmp/.mount_LinphoELXhn2/usr/plugins/platforms/libqxcb.so: (/tmp/.mount_LinphoELXhn2/usr/plugins/platforms/../../lib/libQt5XcbQpa.so.5: symbol _ZN11QFontEngine14bitmapForGlyphEj6QFixedRK10QTransform version Qt_5_PRIVATE_API not defined in file libQt5Gui.so.5 with link time reference)QLibraryPrivate::loadPlugin failed on "/tmp/.mount_LinphoELXhn2/usr/plugins/platforms/libqxcb.so" : "Cannot load library /tmp/.mount_LinphoELXhn2/usr/plugins/platforms/libqxcb.so: (/tmp/.mount_LinphoELXhn2/usr/plugins/platforms/../../lib/libQt5XcbQpa.so.5: symbol _ZN11QFontEngine14bitmapForGlyphEj6QFixedRK10QTransform version Qt_5_PRIVATE_API not defined in file libQt5Gui.so.5 with link time reference)"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.Available platform plugins are: xcb.[1] 7814 abort (core dumped) ./Linphone-4.5.1.AppImage

Hi, AppImage extracts all the files into the /tmp directory, so it's expected that the files exist there (as long as the app runs).
But it seems all Qt files are not from version Qt 5.12.9, the error is that libQt5XcbQpa.so.5 is looking for the function QFontEngine::bitmapForGlyph() in libQt5Gui.so.5 but it's not there. I think that function is maybe 6 years old, perhaps you any other (older) Qt version installed than 5.12.9?

Edit: I greped the sources, the function signature was changed between 5.12.4 and 5.12.5:
in Qt 5.12.4: QImage QFontEngine::bitmapForGlyph(glyph_t, QFixed subPixelPosition, const QTransform&);

in Qt 5.12.5: QImage QFontEngine::bitmapForGlyph(glyph_t, QFixed subPixelPosition, const QTransform&, const QColor &);

since libQt5XcbQpa.so.5 asks for the old one, most likely it's the other way around, i.e. libQt5XcbQpa.so.5 is from 5.12.4 (or older Qt version) and libQt5Gui.so.5 is from 5.12.9.

In the long run the best is to do an apt remove for the apt installed Qt and just stick with Qt’s online installer (because it gives you fresher versiobns).

But you can also try to harmonize them, open a Terminal and type qtdiag (it should pick up the apt installed Qt)
Ser what version is says, then use the MaintenanceTool to downgrade to that version.

Hmm, so apt gave you a piecemeal version of Qt, however enough stuff to error out AppImage.

That older/faulty libQt5XcbQpa.so.5 should be in your /usr/lib/x86_64-linux-gnu anyways, try this in Terminal:

strings /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5 | grep Qt | more

In that list should be some version markers, like Qt_5_PRIVATE_API, Qt_5 and Qt_5.9 or something similar...

Edit: just realized, there's an easier way to establish the version of that apt-flavored partial Qt installation: just list libQt5XcbQpa in Terminal, like this:

ls -l /usr/lib/x86_64-linux-gnu/libQt5Xcb*

this should show what version apt gave you...

@hskoglund
Yes, libQt5XcbQpa.so.5 has Qt_5_PRIVATE_API, Qt_5 and Qt_5.9 in it. Please find the whole output below.

_ZN14QXcbConnection19getQtSelectionOwnerEv_ZN9QtPrivate20QStringList_containsEPK11QStringListRK7QStringN2Qt15CaseSensitivityE_ZN7QObject10startTimerEiN2Qt9TimerTypeE_ZN7QObject7connectEPKS_PKcS1_S3_N2Qt14ConnectionTypeE_ZN11QMetaObject12invokeMethodEP7QObjectPKcN2Qt14ConnectionTypeE22QGenericReturnArgument16QGenericArgumentS7_S7_S7_S7_S7_S7_S7_S7_S7__ZN10QByteArrayC1EiN2Qt14InitializationE_ZN16QCoreApplication13testAttributeEN2Qt20ApplicationAttributeE_ZNK7QString11lastIndexOfE5QChariN2Qt15CaseSensitivityE_ZN16QCoreApplication12setAttributeEN2Qt20ApplicationAttributeEb_ZN7QStringC1EiN2Qt14InitializationE_ZNK20QPlatformIntegration18defaultWindowStateE6QFlagsIN2Qt10WindowTypeEE_ZNK11QMetaMethod6invokeEP7QObjectN2Qt14ConnectionTypeE22QGenericReturnArgument16QGenericArgumentS5_S5_S5_S5_S5_S5_S5_S5_S5__ZN9QKeyEventC1EN6QEvent4TypeEi6QFlagsIN2Qt16KeyboardModifierEEjjjRK7QStringbt_ZN22QWindowSystemInterface22handleContextMenuEventEP7QWindowbRK6QPointS4_6QFlagsIN2Qt16KeyboardModifierEE_ZN22QWindowSystemInterface22handleExtendedKeyEventEP7QWindowmN6QEvent4TypeEi6QFlagsIN2Qt16KeyboardModifierEEjjjRK7QStringbtb_ZNK7QString10startsWithE13QLatin1StringN2Qt15CaseSensitivityE_ZNK7QString7indexOfE13QLatin1StringiN2Qt15CaseSensitivityE_ZNK7QString8splitRefE5QCharNS_13SplitBehaviorEN2Qt15CaseSensitivityE_ZN10QBasicDrag12updateCursorEN2Qt10DropActionE_ZN15QtSharedPointer20ExternalRefCountData9getAndRefEPK7QObject_ZN22QWindowSystemInterface10handleDragEP7QWindowPK9QMimeDataRK6QPoint6QFlagsIN2Qt10DropActionEE_ZNK23QPlatformDragQtResponse10answerRectEv_ZNK23QPlatformDropQtResponse10isAcceptedEv_ZNK23QPlatformDropQtResponse14acceptedActionEv_ZN22QWindowSystemInterface10handleDropEP7QWindowPK9QMimeDataRK6QPoint6QFlagsIN2Qt10DropActionEE_ZNK13QPlatformDrag13defaultActionE6QFlagsIN2Qt10DropActionEES0_INS1_16KeyboardModifierEE_ZN22QWindowSystemInterface29handleScreenOrientationChangeEP7QScreenN2Qt17ScreenOrientationE_ZN7QObject18staticQtMetaObjectE_ZN15QPlatformScreen24setOrientationUpdateMaskE6QFlagsIN2Qt17ScreenOrientationEE_ZN22QWindowSystemInterface21handleWindowActivatedINS_15DefaultDeliveryEEEvP7QWindowN2Qt11FocusReasonE_ZN10QXcbWindow19setMotifWindowFlagsE6QFlagsIN2Qt10WindowTypeEE_ZN10QXcbWindow16handleMouseEventEjRK6QPointS2_6QFlagsIN2Qt16KeyboardModifierEENS4_16MouseEventSourceE_ZN22QWindowSystemInterface16handleMouseEventINS_15DefaultDeliveryEEEvP7QWindowmRK7QPointFS6_6QFlagsIN2Qt11MouseButtonEES7_INS8_16KeyboardModifierEENS8_16MouseEventSourceE_ZN10QXcbWindow24handleButtonReleaseEventEiiiii6QFlagsIN2Qt16KeyboardModifierEEjNS1_16MouseEventSourceE_ZN10QXcbWindow23handleMotionNotifyEventEiiii6QFlagsIN2Qt16KeyboardModifierEEjNS1_16MouseEventSourceE_ZN10QXcbWindow22handleButtonPressEventEiiiii6QFlagsIN2Qt16KeyboardModifierEEjNS1_16MouseEventSourceE_ZN22QWindowSystemInterface16handleWheelEventEP7QWindowmRK7QPointFS4_iN2Qt11OrientationE6QFlagsINS5_16KeyboardModifierEE_ZN10QXcbWindow18handleXIMouseEventEP14xcb_ge_event_tN2Qt16MouseEventSourceE_ZN14QXcbConnection17xiToQtMouseButtonEj_ZN10QXcbWindow24setNetWmStateWindowFlagsE6QFlagsIN2Qt10WindowTypeEE_ZN10QXcbWindow14setWindowStateEN2Qt11WindowStateE_ZThn16_N10QXcbWindow14setWindowStateEN2Qt11WindowStateE_ZN10QXcbWindow19doStartSystemResizeERK6QPointN2Qt6CornerE_ZN10QXcbWindow17startSystemResizeERK6QPointN2Qt6CornerE_ZN14QXcbConnection30startSystemResizeForTouchBeginEjRK6QPointN2Qt6CornerE_ZThn16_N10QXcbWindow17startSystemResizeERK6QPointN2Qt6CornerE_ZN10QXcbWindow15setWmWindowTypeE6QFlagsIN19QXcbWindowFunctions12WmWindowTypeEES0_IN2Qt10WindowTypeEE_ZN22QWindowSystemInterface24handleWindowStateChangedINS_15DefaultDeliveryEEEvP7QWindowN2Qt11WindowStateEi_ZN10QXcbWindow14setWindowFlagsE6QFlagsIN2Qt10WindowTypeEE_ZThn16_N10QXcbWindow14setWindowFlagsE6QFlagsIN2Qt10WindowTypeEE_ZN6QImage23convertToFormat_inplaceENS_6FormatE6QFlagsIN2Qt19ImageConversionFlagEE_ZNK6QImage22convertToFormat_helperENS_6FormatE6QFlagsIN2Qt19ImageConversionFlagEE_ZN15QPlatformWindow30handleContentOrientationChangeEN2Qt17ScreenOrientationE_ZN6QColorC1EN2Qt11GlobalColorE_ZN22QGuiApplicationPrivate15getPixmapCursorEN2Qt11CursorShapeE_ZNK6QImage15createAlphaMaskE6QFlagsIN2Qt19ImageConversionFlagEE_ZN7QPixmap16fromImageInPlaceER6QImage6QFlagsIN2Qt19ImageConversionFlagEE_ZN22QWindowSystemInterface16handleWheelEventEP7QWindowmRK7QPointFS4_6QPointS5_6QFlagsIN2Qt16KeyboardModifierEENS7_11ScrollPhaseENS7_16MouseEventSourceEb_ZN22QWindowSystemInterface17handleTabletEventEP7QWindowmRK7QPointFS4_ii6QFlagsIN2Qt11MouseButtonEEdiiddixS5_INS6_16KeyboardModifierEE_ZN16QLoggingCategory10setEnabledE9QtMsgTypeb_ZN22QWindowSystemInterface16handleTouchEventINS_15DefaultDeliveryEEEvP7QWindowmP12QTouchDeviceRK5QListINS_10TouchPointEE6QFlagsIN2Qt16KeyboardModifierEE_ZNK7QString7compareERKS_N2Qt15CaseSensitivityE_ZN14QFactoryLoaderC1EPKcRK7QStringN2Qt15CaseSensitivityE_ZN9QtPrivate16QStringList_joinEPK11QStringListPK5QChari_ZN6QBrushC1EN2Qt11GlobalColorENS0_10BrushStyleE_ZN6QBrushC1ERK6QColorN2Qt10BrushStyleE_ZN9QMetaType25registerConverterFunctionEPKN9QtPrivate25AbstractConverterFunctionEii_ZN9QtPrivate28QStringList_removeDuplicatesEP11QStringList_ZNK7QString5splitE5QCharNS_13SplitBehaviorEN2Qt15CaseSensitivityE_ZN7QObject11connectImplEPKS_PPvS1_S3_PN9QtPrivate15QSlotObjectBaseEN2Qt14ConnectionTypeEPKiPK11QMetaObject_ZNK7QString8endsWithE13QLatin1StringN2Qt15CaseSensitivityE_ZN6QImage4fillEN2Qt11GlobalColorE_ZNK7QString7indexOfE5QChariN2Qt15CaseSensitivityE_ZN20QEventDispatcherGlib13registerTimerEiiN2Qt9TimerTypeEP7QObject_ZN20QEventDispatcherUNIX13registerTimerEiiN2Qt9TimerTypeEP7QObject_ZNK6QImage11transformedERK10QTransformN2Qt18TransformationModeElibQt5Gui.so.5libQt5DBus.so.5libQt5Core.so.5libQt5XcbQpa.so.5Qt_5_PRIVATE_APIQt_5Qt_5.9Qt: XKEYBOARD extension not present on the X server.Qt: Failed to initialize XKB extensionQt: Unsupported XKB version (We want %d %d, but X server has %d %d)Qt: failed to select notify events from xcb-xkbQt: Couldn't interpret the _XKB_RULES_NAMES propertyQt: Failed to compile US keymap, shortcut handling with non-Latin keyboard layouts may not be fully functional!Qt: failed to retrieve the virtual modifier names from XKBQt: failed to retrieve the virtual modifier map from XKBQt: failed to get modifier mappingQt: failed to retrieve the keyboard mapping from XKBQt: Failed to create XKB context!Qt: Could not determine keyboard configuration data from X server, will use hard-coded keymap configuration.Qt: Failed to compile a keymap!Qt: Failed to create xkb state!Qt: couldn't get core keyboard device infoXInput version %d.%d is available and Qt supports 2.2 or greaterQt: Session management error: %sorg.qt-project.Qt.QPA.Xcb.QXcbGlIntegrationFactoryInterface.5.5QtMetaTypePrivate::QSequentialIterableImpl <annotation value="QDBusMenuLayoutItem" name="org.qtproject.QtDBus.QtTypeName.Out1"/> <annotation value="QList&lt;int&gt;" name="org.qtproject.QtDBus.QtTypeName.In0"/> <annotation value="QDBusMenuItemList" name="org.qtproject.QtDBus.QtTypeName.Out0"/> <annotation value="QList&lt;QDBusMenuEvent&gt;" name="org.qtproject.QtDBus.QtTypeName.In0"/> <annotation value="QList&lt;int&gt;" name="org.qtproject.QtDBus.QtTypeName.Out0"/> <annotation value="QList&lt;int&gt;" name="org.qtproject.QtDBus.QtTypeName.In0"/> <annotation value="QList&lt;int&gt;" name="org.qtproject.QtDBus.QtTypeName.Out0"/> <annotation value="QList&lt;int&gt;" name="org.qtproject.QtDBus.QtTypeName.Out1"/> <annotation value="QDBusMenuItemList" name="org.qtproject.QtDBus.QtTypeName.In0"/> <annotation value="QDBusMenuItemKeysList" name="org.qtproject.QtDBus.QtTypeName.In1"/> <annotation value="QXdgDBusImageVector" name="org.qtproject.QtDBus.QtTypeName"/> <annotation value="QXdgDBusImageVector" name="org.qtproject.QtDBus.QtTypeName"/> <annotation value="QXdgDBusImageVector" name="org.qtproject.QtDBus.QtTypeName"/> <annotation value="QXdgDBusToolTipStruct" name="org.qtproject.QtDBus.QtTypeName"/>Note that Qt no longer ships fonts. Deploy some (from http://dejavu-fonts.org for example) or switch to fontconfig.QtMetaTypePrivate::QPairVariantInterfaceImplQtMetaTypePrivate::QAssociativeIterableImplWARNING Qt AtSpiAdaptor: Could not find accessible on path: WARNING Qt AtSpiAdaptor: Could not find application interface for: WARNING Qt AtSpiAdaptor: Could not find table interface for: WARNING Qt AtSpiAdaptor: Accessible invalid: <annotation value="QSpiAttributeSet" name="org.qtproject.QtDBus.QtTypeName.Out0"/> <annotation value="QSpiAttributeSet" name="org.qtproject.QtDBus.QtTypeName.Out0"/> <annotation value="QSpiRangeList" name="org.qtproject.QtDBus.QtTypeName.Out0"/> <annotation value="QSpiAttributeSet" name="org.qtproject.QtDBus.QtTypeName.Out0"/> <annotation value="QSpiAttributeSet" name="org.qtproject.QtDBus.QtTypeName.Out0"/> <annotation value="QSpiObjectReference" name="org.qtproject.QtDBus.QtTypeName"/> <annotation value="QSpiObjectReference" name="org.qtproject.QtDBus.QtTypeName"/> <annotation value="QSpiObjectReference" name="org.qtproject.QtDBus.QtTypeName.Out0"/> <annotation value="QSpiObjectReference" name="org.qtproject.QtDBus.QtTypeName.Out0"/> <annotation value="QSpiObjectReference" name="org.qtproject.QtDBus.QtTypeName.Out0"/> <annotation value="QSpiIntList" name="org.qtproject.QtDBus.QtTypeName.Out0"/> <annotation value="QSpiIntList" name="org.qtproject.QtDBus.QtTypeName.Out0"/> <annotation value="QSpiObjectReference" name="org.qtproject.QtDBus.QtTypeName.Out0"/> <annotation value="QSpiRect" name="org.qtproject.QtDBus.QtTypeName.Out0"/> <annotation value="QSpiActionArray" name="org.qtproject.QtDBus.QtTypeName.Out0"/> <annotation value="QSpiObjectReference" name="org.qtproject.QtDBus.QtTypeName"/> <annotation value="QSpiObjectReference" name="org.qtproject.QtDBus.QtTypeName.Out0"/> <annotation value="QSpiObjectReferenceArray" name="org.qtproject.QtDBus.QtTypeName.Out0"/> <annotation value="QSpiRelationArray" name="org.qtproject.QtDBus.QtTypeName.Out0"/> <annotation value="QSpiUIntList" name="org.qtproject.QtDBus.QtTypeName.Out0"/> <annotation value="QSpiAttributeSet" name="org.qtproject.QtDBus.QtTypeName.Out0"/> <annotation value="QSpiObjectReference" name="org.qtproject.QtDBus.QtTypeName.Out0"/> <annotation value="QSpiAccessibleCacheArray" name="org.qtproject.QtDBus.QtTypeName.Out0"/> <annotation value="QSpiAccessibleCacheItem" name="org.qtproject.QtDBus.QtTypeName.Out0"/> <annotation value="QSpiObjectReference" name="org.qtproject.QtDBus.QtTypeName.Out0"/> <annotation value="QSpiDeviceEvent" name="org.qtproject.QtDBus.QtTypeName.In0"/> <annotation value="QSpiDeviceEvent" name="org.qtproject.QtDBus.QtTypeName.In0"/>

Does that mean that this library is for Qt 5.9? And is not compatible with Qt 5.12.9 that we have installed with Qt installer?

We're getting the similar results for the ls command,

-rw-r--r-- 1 root root 1602 Feb 7 2020 /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.prllrwxrwxrwx 1 root root 21 Feb 7 2020 /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so -> libQt5XcbQpa.so.5.9.5lrwxrwxrwx 1 root root 21 Feb 7 2020 /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5 -> libQt5XcbQpa.so.5.9.5lrwxrwxrwx 1 root root 21 Feb 7 2020 /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5.9 -> libQt5XcbQpa.so.5.9.5-rw-r--r-- 1 root root 1070840 Feb 7 2020 /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5.9.5

Indeed, the apt version of Qt you've got is 5.9.5. which does not play well with 5.12.9 :-(

Easiest short-term solution to get AppImage working is to try downgrade your 5.12.9 to 5.9.5 (with a bit of luck any 5.9.x version will do, but see if you can find 5.9.5 first).

(Long-term: try purging all apt-flavored Qt stuff from your Ubuntu system and rely solely on Qt's online installer.)

@hskoglund Thanks for the confirmation!
Actually as per the application doc, its required to be 5.12 or greater,
For Desktop : you will need Qt5 (5.12 or newer). C++11 support is required!

I've uninstalled qt5-doc and other dependent packages installed via apt and built it again but xcb error is still there.
I'm checking if there is anything else remained to be removed.
Will update.