[Bug]: Nextcloud Desktop client 33.0.2 crash during Server upgrade

[theking2]

⚠️ Before submitting, please verify the following: ⚠️

• This is a bug, not a question or a configuration issue.
• This issue is not already reported on Github (I've searched it).
• Nextcloud Server and Desktop Client are up to date. See Server Maintenance and Release Schedule and Desktop Releases for supported versions.
• I agree to follow Nextcloud's Code of Conduct

Bug description

Nextcloud Desktop client (AppImage 33.0.2 on Fedora 43) crashes during a succesfull server upgrade from 33.0.0 to 33.0.2.
...

Steps to reproduce

1. Connect Nextcloud desktop client to an existing Nextcloud server version 33.0.0
2. Start the upgrader process on the serer
3. During upgrade the client crashes
   ...

Expected behavior

Client loses connection during maintenacne but startes syncing as soon as maintenance is stopped
...

Which files are affected by this bug

none

Operating system

Linux

Which version of the operating system you are running.

Fedora 43 6.19 KDE Plasma 6.6.3

Package

Official Linux AppImage

Nextcloud Server version

33.0.0 -> 33.0.2

Nextcloud Desktop Client version

33.0.2

Is this bug present after an update or on a fresh install?

Fresh desktop client install

Are you using the Nextcloud Server Encryption module?

Encryption is Disabled

Are you using an external user-backend?

• Default internal user-backend
• LDAP/ Active Directory
• SSO - SAML
• Other

Nextcloud Server logs

After the update the logs are empty

Additional info

Crashed process viewer:

           PID: 47481 (AppRun)
           UID: 1000 (j)
           GID: 1000 (j)
        Signal: 11 (SEGV)
     Timestamp: Wed 2026-04-08 09:28:50 CEST (16s ago)
  Command Line: Applications/Nextcloud-33.0.2-x86_64.AppImage
    Executable: /tmp/.mount_NextclnmjBdm/usr/bin/nextcloud
 Control Group: /user.slice/user-1000.slice/user@1000.service/app.slice/app-org.kde.konsole-6904.scope/tab(12676).scope
          Unit: user@1000.service
     User Unit: app-org.kde.konsole-6904.scope
         Slice: user-1000.slice
     Owner UID: 1000 (j)
       Boot ID: 734fa5640ef9470d903f957617be036e
    Machine ID: 97b658c4dc2d411eabf1b2a547c49718
      Hostname: ws-study
       Storage: /var/lib/systemd/coredump/core.AppRun.1000.734fa5640ef9470d903f957617be036e.47481.1775633330000000.zst (present)
  Size on Disk: 30.2M
       Message: Process 47481 (AppRun) of user 1000 dumped core.
                
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-glx.so.0 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-glx.so.0
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-xkb.so.1 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-xkb.so.1
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-shape.so.0 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-shape.so.0
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-render.so.0 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-render.so.0
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-xfixes.so.0 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-xfixes.so.0
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-sync.so.1 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-sync.so.1
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-shm.so.0 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-shm.so.0
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-render-util.so.0 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-render-util.so.0
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-randr.so.0 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-randr.so.0
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-keysyms.so.1 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-keysyms.so.1
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-image.so.0 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-image.so.0
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-util.so.1 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-util.so.1
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-icccm.so.4 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxcb-icccm.so.4
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxkbcommon-x11.so.0 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxkbcommon-x11.so.0
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libblkid.so.1 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libblkid.so.1
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libcap.so.2 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libcap.so.2
                Module /tmp/.mount_NextclnmjBdm/usr/lib/liblz4.so.1 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/liblz4.so.1
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libgomp.so.1 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libgomp.so.1
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libcrypto.so.1.1 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libcrypto.so.1.1
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libkeyutils.so.1 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libkeyutils.so.1
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libkrb5support.so.0 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libkrb5support.so.0
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libk5crypto.so.3 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libk5crypto.so.3
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libkrb5.so.3 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libkrb5.so.3
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libselinux.so.1 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libselinux.so.1
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libmount.so.1 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libmount.so.1
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libsystemd.so.0 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libsystemd.so.0
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libgssapi_krb5.so.2 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libgssapi_krb5.so.2
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libGLdispatch.so.0 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libGLdispatch.so.0
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libEGL.so.1 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libEGL.so.1
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxkbfile.so.1 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxkbfile.so.1
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxshmfence.so.1 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libudev.so.1 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libudev.so.1
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libXi.so.6 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libXi.so.6
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libXtst.so.6 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libXtst.so.6
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libXrender.so.1 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libXrender.so.1
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libXrandr.so.2 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libXrandr.so.2
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libXfixes.so.3 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libXfixes.so.3
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libXext.so.6 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libXext.so.6
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libXdamage.so.1 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libXdamage.so.1
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libXcomposite.so.1 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libXcomposite.so.1
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libatomic.so.1 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libatomic.so.1
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxkbcommon.so.0 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libxkbcommon.so.0
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libOpenGL.so.0 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libOpenGL.so.0
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libGLX.so.0 without build-id.
                Module /tmp/.mount_NextclnmjBdm/usr/lib/libGLX.so.0
                Module libnss_resolve.so.2 from rpm systemd-258.7-1.fc43.x86_64
                Module libnss_mdns4_minimal.so.2 from rpm nss-mdns-0.15.1-27.fc43.x86_64
                Module libnss_myhostname.so.2 from rpm systemd-258.7-1.fc43.x86_64
                Module libGL.so.1 from rpm libglvnd-1.7.0-8.fc43.x86_64
                Module libVkLayer_MESA_device_select.so from rpm mesa-25.3.6-3.fc43.x86_64
                Module libvulkan_nouveau.so from rpm mesa-25.3.6-3.fc43.x86_64
                Module libvulkan_lvp.so from rpm mesa-25.3.6-3.fc43.x86_64
                Module libvulkan_dzn.so from rpm mesa-25.3.6-3.fc43.x86_64
                Module libdisplay-info.so.2 from rpm libdisplay-info-0.2.0-4.fc43.x86_64
                Module libwayland-client.so.0 from rpm wayland-1.24.0-1.fc43.x86_64
                Module libvulkan.so.1 from rpm vulkan-loader-1.4.341.0-1.fc43.x86_64
                Module libtinfo.so.6 from rpm ncurses-6.5-7.20250614.fc43.x86_64
                Module libpciaccess.so.0 from rpm libpciaccess-0.16-16.fc43.x86_64
                Module libedit.so.0 from rpm libedit-3.1-57.20251016cvs.fc43.x86_64
                Module libdrm_intel.so.1 from rpm libdrm-2.4.131-1.fc43.x86_64
                Module libelf.so.1 from rpm elfutils-0.194-1.fc43.x86_64
                Module libdrm_amdgpu.so.1 from rpm libdrm-2.4.131-1.fc43.x86_64
                Module libsensors.so.4 from rpm lm_sensors-3.6.0-23.fc43.x86_64
                Module libSPIRV-Tools.so from rpm spirv-tools-2026.1-2.fc43.x86_64
                Module libxcb-present.so.0 from rpm libxcb-1.17.0-6.fc43.x86_64
                Module libXxf86vm.so.1 from rpm libXxf86vm-1.1.6-3.fc43.x86_64
                Module libdrm.so.2 from rpm libdrm-2.4.131-1.fc43.x86_64
                Module libgallium-25.3.6.so from rpm mesa-25.3.6-3.fc43.x86_64
                Module libGLX_mesa.so.0 from rpm mesa-25.3.6-3.fc43.x86_64
                Module libX11-xcb.so.1 from rpm libX11-1.8.13-1.fc43.x86_64
                Module libcom_err.so.2 from rpm e2fsprogs-1.47.3-2.fc43.x86_64
                Module libxml2.so.2 from rpm libxml2-2.12.10-5.fc43.x86_64
                Module libXau.so.6 from rpm libXau-1.0.12-3.fc43.x86_64
                Module libasound.so.2 from rpm alsa-lib-1.2.15.3-1.fc43.x86_64
                Module libxcb.so.1 from rpm libxcb-1.17.0-6.fc43.x86_64
                Module libfontconfig.so.1 from rpm fontconfig-2.17.0-3.fc43.x86_64
                Module libX11.so.6 from rpm libX11-1.8.13-1.fc43.x86_64
                Module libxcb-dri3.so.0 from rpm libxcb-1.17.0-6.fc43.x86_64
                Stack trace of thread 47481:
                #0  0x00007fd7ecc97a85 n/a (/tmp/.mount_NextclnmjBdm/usr/lib/libQt6Network.so.6 + 0x97a85)
                #1  0x00007fd7ef78a044 n/a (/tmp/.mount_NextclnmjBdm/usr/lib/libnextcloudsync.so.0 + 0x58a044)
                #2  0x00007fd7ef717bae n/a (/tmp/.mount_NextclnmjBdm/usr/lib/libnextcloudsync.so.0 + 0x517bae)
                #3  0x00007fd7ef719ae2 n/a (/tmp/.mount_NextclnmjBdm/usr/lib/libnextcloudsync.so.0 + 0x519ae2)
                #4  0x00007fd7ef717c20 n/a (/tmp/.mount_NextclnmjBdm/usr/lib/libnextcloudsync.so.0 + 0x517c20)
                #5  0x00007fd7ef714b92 n/a (/tmp/.mount_NextclnmjBdm/usr/lib/libnextcloudsync.so.0 + 0x514b92)
                #6  0x00007fd7ef70fb87 n/a (/tmp/.mount_NextclnmjBdm/usr/lib/libnextcloudsync.so.0 + 0x50fb87)
                #7  0x00007fd7ec609222 n/a (/tmp/.mount_NextclnmjBdm/usr/lib/libQt6Core.so.6 + 0x209222)
                #8  0x00007fd7ec5fabdf n/a (/tmp/.mount_NextclnmjBdm/usr/lib/libQt6Core.so.6 + 0x1fabdf)
                #9  0x00007fd7ee392eea n/a (/tmp/.mount_NextclnmjBdm/usr/lib/libQt6Widgets.so.6 + 0x192eea)
                ELF object binary architecture: AMD x86-64

Coredump: https://cloud.sbw.media/index.php/s/tKLYrAW9ZxdcgW2

[nilsding]

Thanks for the coredump, this allowed to complete the logged stack trace with symbols for future reference:

Thread 1 (LWP 47481):
#0  0x00007fd7ecc97a85 in QNetworkReply::request() const () from /tmp/.mount_NextclnmjBdm/usr/bin/../lib/libQt6Network.so.6
#1  0x00007fd7ef7271f7 in OCC::LsColJob::finished() () from /tmp/.mount_NextclnmjBdm/usr/bin/../lib/libnextcloudsync.so.0
#2  0x00007fd7ef78a044 in OCC::AbstractNetworkJob::slotFinished() () from /tmp/.mount_NextclnmjBdm/usr/bin/../lib/libnextcloudsync.so.0
#3  0x00007fd7ef717bae in QtPrivate::FunctorCall<std::integer_sequence<unsigned long>, QtPrivate::List<>, void, void (OCC::AbstractNetworkJob::*)()>::call(void (OCC::AbstractNetworkJob::*)(), OCC::AbstractNetworkJob*, void**)::{lambda()#1}::operator()() const () from /tmp/.mount_NextclnmjBdm/usr/bin/../lib/libnextcloudsync.so.0
#4  0x00007fd7ef719ae2 in void QtPrivate::FunctorCallBase::call_internal<void, QtPrivate::FunctorCall<std::integer_sequence<unsigned long>, QtPrivate::List<>, void, void (OCC::AbstractNetworkJob::*)()>::call(void (OCC::AbstractNetworkJob::*)(), OCC::AbstractNetworkJob*, void**)::{lambda()#1}>(void**, QtPrivate::FunctorCall<std::integer_sequence<unsigned long>, QtPrivate::List<>, void, void (OCC::AbstractNetworkJob::*)()>::call(void (OCC::AbstractNetworkJob::*)(), OCC::AbstractNetworkJob*, void**)::{lambda()#1}&&) () from /tmp/.mount_NextclnmjBdm/usr/bin/../lib/libnextcloudsync.so.0
#5  0x00007fd7ef717c20 in QtPrivate::FunctorCall<std::integer_sequence<unsigned long>, QtPrivate::List<>, void, void (OCC::AbstractNetworkJob::*)()>::call(void (OCC::AbstractNetworkJob::*)(), OCC::AbstractNetworkJob*, void**) () from /tmp/.mount_NextclnmjBdm/usr/bin/../lib/libnextcloudsync.so.0
#6  0x00007fd7ef714b92 in void QtPrivate::FunctionPointer<void (OCC::AbstractNetworkJob::*)()>::call<QtPrivate::List<>, void>(void (OCC::AbstractNetworkJob::*)(), OCC::AbstractNetworkJob*, void**) () from /tmp/.mount_NextclnmjBdm/usr/bin/../lib/libnextcloudsync.so.0
#7  0x00007fd7ef70fb87 in ?? () from /tmp/.mount_NextclnmjBdm/usr/bin/../lib/libnextcloudsync.so.0
#8  0x00007fd7ec609222 in ?? () from /tmp/.mount_NextclnmjBdm/usr/bin/../lib/libQt6Core.so.6
#9  0x00007fd7ec5fabdf in QObject::event(QEvent*) () from /tmp/.mount_NextclnmjBdm/usr/bin/../lib/libQt6Core.so.6
#10 0x00007fd7ee392eea in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /tmp/.mount_NextclnmjBdm/usr/bin/../lib/libQt6Widgets.so.6
#11 0x00007fd7ec5a01a8 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /tmp/.mount_NextclnmjBdm/usr/bin/../lib/libQt6Core.so.6
#12 0x00007fd7ec5a3c1e in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () from /tmp/.mount_NextclnmjBdm/usr/bin/../lib/libQt6Core.so.6
#13 0x00007fd7ec8c7667 in ?? () from /tmp/.mount_NextclnmjBdm/usr/bin/../lib/libQt6Core.so.6
#14 0x00007fd7e9907a76 in ?? () from /tmp/.mount_NextclnmjBdm/usr/bin/../lib/libglib-2.0.so.0
#15 0x00007fd7e990ade7 in ?? () from /tmp/.mount_NextclnmjBdm/usr/bin/../lib/libglib-2.0.so.0
#16 0x00007fd7e990b4fc in g_main_context_iteration () from /tmp/.mount_NextclnmjBdm/usr/bin/../lib/libglib-2.0.so.0
#17 0x00007fd7ec8c6dd3 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /tmp/.mount_NextclnmjBdm/usr/bin/../lib/libQt6Core.so.6
#18 0x00007fd7ec5acefb in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /tmp/.mount_NextclnmjBdm/usr/bin/../lib/libQt6Core.so.6
#19 0x00007fd7ec5a85de in QCoreApplication::exec() () from /tmp/.mount_NextclnmjBdm/usr/bin/../lib/libQt6Core.so.6
#20 0x00005569b68188c5 in ?? ()
#21 0x00007fd7ebe105b5 in ?? ()
#22 0x00005569b6df5da8 in ?? ()
#23 0x00007fff37903808 in ?? ()
#24 0x00000001b6df5d28 in ?? ()
#25 0x00005569b6817b75 in ?? ()
#26 0x0000000000000000 in ?? ()

Are there any client logs from the time of the crash in ~/.config/Nextcloud/logs?

[theking2]

I'm afraid not.