Hi Dominique, my son complained about kdenlive not working (crashing on start) with a traceback similar to: Application: Kdenlive (kdenlive), signal: Segmentation fault Content of s_kcrashErrorMessage: [Current thread is 1 (Thread 0x7f9e5bc85980 (LWP 24123))] [KCrash Handler] #6 0x00007f9e5ffca9ad in Mlt::Properties::set(char const*, int) (this=0x0, name=0x55fb1e469059 "scrub_audio", value=0) at /usr/src/debug/libmlt-7.0.1-2.1.x86_64/src/mlt++/MltProperties.cpp:178 #7 0x000055fb1e103653 in GLWidget::setProducer(std::shared_ptr<Mlt::Producer> const&, bool, int) (this=0x55fb2237c6f0, producer=<optimized out>, isActive=<optimized out>, position=<optimized out>) at /usr/include/c++/11/bits/shared_ptr_base.h:1295 #8 0x000055fb1e3171db in Monitor::setProducer(std::shared_ptr<Mlt::Producer>, int) (pos=0, producer=std::shared_ptr<class Mlt::Producer> (use count 2, weak count 0) = {...}, this=0x55fb2237c160) at /usr/src/debug/kdenlive-21.08.0-1.1.x86_64/src/monitor/monitor.cpp:2392 #9 ProjectManager::updateTimeline(int, int) [clone .constprop.0] (this=this@entry=0x55fb209ae8d0, pos=pos@entry=0, scrollPos=-1) at /usr/src/debug/kdenlive-21.08.0-1.1.x86_64/src/project/projectmanager.cpp:982 #10 0x000055fb1e15d19f in ProjectManager::newFile(QString, bool) (this=0x55fb209ae8d0, profileName=..., showProjectSettings=<optimized out>) at /usr/src/debug/kdenlive-21.08.0-1.1.x86_64/src/project/projectmanager.cpp:228 #11 0x000055fb1e15d6bf in ProjectManager::newFile(bool) (this=0x55fb209ae8d0, showProjectSettings=<optimized out>) at /usr/src/debug/kdenlive-21.08.0-1.1.x86_64/src/project/projectmanager.cpp:139 #12 0x000055fb1df2880d in ProjectManager::slotLoadOnOpen() (this=0x55fb209ae8d0) at /usr/src/debug/kdenlive-21.08.0-1.1.x86_64/src/project/projectmanager.cpp:109 #13 ProjectManager::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) (_o=0x55fb209ae8d0, _id=<optimized out>, _a=0x55fb235bd9f8, _c=<optimized out>) at /usr/src/debug/kdenlive-21.08.0-1.1.x86_64/build/src/kdenliveLib_autogen/QV7S676PVK/moc_projectmanager.cpp:223 #14 0x00007f9e5e65cf7e in QObject::event(QEvent*) (this=0x55fb209ae8d0, e=0x55fb235bd9b0) at kernel/qobject.cpp:1314 #15 0x00007f9e5f87ba7f in QApplicationPrivate::notify_helper(QObject*, QEvent*) (this=<optimized out>, receiver=0x55fb209ae8d0, e=0x55fb235bd9b0) at kernel/qapplication.cpp:3632 #16 0x00007f9e5e63098a in QCoreApplication::notifyInternal2(QObject*, QEvent*) (receiver=0x55fb209ae8d0, event=0x55fb235bd9b0) at kernel/qcoreapplication.cpp:1064 #17 0x00007f9e5e6339d7 in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) (receiver=0x0, event_type=0, data=0x55fb200e50d0) at kernel/qcoreapplication.cpp:1821 #18 0x00007f9e5e6887e3 in postEventSourceDispatch(GSource*, GSourceFunc, gpointer) (s=s@entry=0x55fb20263fd0) at kernel/qeventdispatcher_glib.cpp:277 #19 0x00007f9e5c67b80f in g_main_dispatch (context=0x7f9e54005000) at ../glib/gmain.c:3337 #20 g_main_context_dispatch (context=0x7f9e54005000) at ../glib/gmain.c:4055 #21 0x00007f9e5c67bb98 in g_main_context_iterate (context=context@entry=0x7f9e54005000, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../glib/gmain.c:4131 #22 0x00007f9e5c67bc4f in g_main_context_iteration (context=0x7f9e54005000, may_block=1) at ../glib/gmain.c:4196 #23 0x00007f9e5e687e64 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x55fb20260350, flags=...) at kernel/qeventdispatcher_glib.cpp:423 #24 0x00007f9e5e62f38b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7ffee5f3d290, flags=..., flags@entry=...) at ../../include/QtCore/../../src/corelib/global/qflags.h:69 #25 0x00007f9e5e637670 in QCoreApplication::exec() () at ../../include/QtCore/../../src/corelib/global/qflags.h:121 #26 0x00007f9e5f11d19c in QGuiApplication::exec() () at kernel/qguiapplication.cpp:1867 #27 0x00007f9e5f87b9f5 in QApplication::exec() () at kernel/qapplication.cpp:2824 #28 0x000055fb1debf9eb in main(int, char**) (argc=<optimized out>, argv=0x7ffee5f3d638) at /usr/src/debug/kdenlive-21.08.0-1.1.x86_64/src/main.cpp:278 [Inferior 1 (process 24123) detached] Rebuilding libmlt fixed that for me. You might want to trigger a libmlt on Factory. Cheers, Pete