I was working on a project, and tried to remove a clip together with audio track and overlay title by ctrl-selecting all three and pressing Del on the keyboard. The audio track went away but the video and title remained. As they couldn't be deleted nor moved, I tried saving the project and re-opening it. When opening, it crashes before displaying the timeline but after the project bin has been loaded. I tried dropping all items from the cache, and even removed the clip from the drive. Kdenlive informs me about this on startup, and I select "remove clip", but it still crashes when accepting the dialog. Installed versions: libmlt++3: 6.3.0+git201610101603~ubuntu16.04.1 kdenlive: 4:16.08.2~ubuntu16.04.1 Thread 1 "kdenlive" received signal SIGSEGV, Segmentation fault. 0x00007ffff6dc05c0 in Mlt::Properties::get(char const*) () from /usr/lib/x86_64-linux-gnu/libmlt++.so.3 --- (gdb) backtrace #0 0x00007ffff6dc05c0 in Mlt::Properties::get(char const*) () from /usr/lib/x86_64-linux-gnu/libmlt++.so.3 #1 0x00000000005c2e6a in Track::info (this=0x0) at /build/kdenlive-_W39Rj/kdenlive-16.08.2~ubuntu16.04.1/src/timeline/track.cpp:579 #2 0x00000000005b4beb in Timeline::getTracksInfo (this=0x3d74500) at /build/kdenlive-_W39Rj/kdenlive-16.08.2~ubuntu16.04.1/src/timeline/timeline.cpp:682 #3 0x0000000000524fdf in TransitionSettings::updateProjectFormat (this=0x2021890) at /build/kdenlive-_W39Rj/kdenlive-16.08.2~ubuntu16.04.1/src/project/transitionsettings.cpp:125 #4 0x00000000008265a7 in MainWindow::connectDocument (this=0xd32fa0) at /build/kdenlive-_W39Rj/kdenlive-16.08.2~ubuntu16.04.1/src/mainwindow.cpp:1784 #5 0x0000000000521240 in ProjectManager::doOpenFile (this=this@entry=0xca19a0, url=..., stale=<optimized out>, stale@entry=0x0) at /build/kdenlive-_W39Rj/kdenlive-16.08.2~ubuntu16.04.1/src/project/projectmanager.cpp:549 #6 0x0000000000522d6f in ProjectManager::openFile (this=0xca19a0, url=...) at /build/kdenlive-_W39Rj/kdenlive-16.08.2~ubuntu16.04.1/src/project/projectmanager.cpp:489 #7 0x000000000086aee1 in ProjectManager::qt_static_metacall (_o=0xca19a0, _c=<optimized out>, _id=<optimized out>, _a=<optimized out>) at /build/kdenlive-_W39Rj/kdenlive-16.08.2~ubuntu16.04.1/obj-x86_64-linux-gnu/src/moc_projectmanager.cpp:184 #8 0x00007ffff2320d2a in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #9 0x00007ffff4e992e2 in KRecentFilesAction::urlSelected(QUrl const&) () from /usr/lib/x86_64-linux-gnu/libKF5ConfigWidgets.so.5 #10 0x00007ffff4e99cb8 in ?? () from /usr/lib/x86_64-linux-gnu/libKF5ConfigWidgets.so.5 #11 0x00007ffff4e9a07b in ?? () from /usr/lib/x86_64-linux-gnu/libKF5ConfigWidgets.so.5 #12 0x00007ffff2320d2a in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #13 0x00007ffff4096ddf in KSelectAction::triggered(QAction*) () from /usr/lib/x86_64-linux-gnu/libKF5WidgetsAddons.so.5 #14 0x00007ffff4099ebd in KSelectAction::actionTriggered(QAction*) () from /usr/lib/x86_64-linux-gnu/libKF5WidgetsAddons.so.5 #15 0x00007ffff2320baf in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #16 0x00007ffff38a095f in QActionGroup::triggered(QAction*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #17 0x00007ffff38a15d9 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #18 0x00007ffff2320d2a in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #19 0x00007ffff389d412 in QAction::triggered(bool) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #20 0x00007ffff389f898 in QAction::activate(QAction::ActionEvent) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #21 0x00007ffff3a21e12 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #22 0x00007ffff3a280ac in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #23 0x00007ffff3a2c020 in QMenu::mouseReleaseEvent(QMouseEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #24 0x00007ffff38e9f88 in QWidget::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #25 0x00007ffff3a2ca73 in QMenu::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #26 0x00007ffff38a705c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #27 0x00007ffff38acc19 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #28 0x00007ffff22f238b in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #29 0x00007ffff38abb32 in QApplicationPrivate::sendMouseEvent(QWidget*, QMouseEvent*, QWidget*, QWidget*, QWidget**, QPointer<QWidget>&, bool) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #30 0x00007ffff39048dd in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #31 0x00007ffff3906b3b in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #32 0x00007ffff38a705c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #33 0x00007ffff38ac516 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #34 0x00007ffff22f238b in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #35 0x00007ffff26344e1 in QGuiApplicationPrivate::processMouseEvent(QWindowSystemInterfacePrivate::MouseEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5 #36 0x00007ffff26361a5 in QGuiApplicationPrivate::processWindowSystemEvent(QWindowSystemInterfacePrivate::WindowSystemEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5 #37 0x00007ffff2619f08 in QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5 #38 0x00007fffe5777060 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5 #39 0x00007fffee6381a7 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #40 0x00007fffee638400 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 ---Type <return> to continue, or q <return> to quit--- #41 0x00007fffee6384ac in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #42 0x00007ffff23487cf in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #43 0x00007ffff22efb4a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #44 0x00007ffff3a26e00 in QMenu::exec(QPoint const&, QAction*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #45 0x00007ffff3a6918e in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #46 0x00007ffff2320d2a in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #47 0x00007ffff39a3fb7 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #48 0x00007ffff39a4111 in QAbstractButton::mousePressEvent(QMouseEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #49 0x00007ffff3a69f7f in QToolButton::mousePressEvent(QMouseEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #50 0x00007ffff38ea3cf in QWidget::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #51 0x00007ffff3a6a229 in QToolButton::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #52 0x00007ffff38a705c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #53 0x00007ffff38acc19 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #54 0x00007ffff22f238b in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #55 0x00007ffff38abb32 in QApplicationPrivate::sendMouseEvent(QWidget*, QMouseEvent*, QWidget*, QWidget*, QWidget**, QPointer<QWidget>&, bool) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #56 0x00007ffff390457b in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #57 0x00007ffff3906b3b in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #58 0x00007ffff38a705c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #59 0x00007ffff38ac516 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5 #60 0x00007ffff22f238b in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #61 0x00007ffff26344e1 in QGuiApplicationPrivate::processMouseEvent(QWindowSystemInterfacePrivate::MouseEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5 #62 0x00007ffff26361a5 in QGuiApplicationPrivate::processWindowSystemEvent(QWindowSystemInterfacePrivate::WindowSystemEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5 #63 0x00007ffff2619f08 in QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5 #64 0x00007fffe5777060 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5 #65 0x00007fffee6381a7 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #66 0x00007fffee638400 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #67 0x00007fffee6384ac in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #68 0x00007ffff23487cf in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #69 0x00007ffff22efb4a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #70 0x00007ffff22f7bec in QCoreApplication::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #71 0x000000000048a24a in main (argc=1, argv=<optimized out>) at /build/kdenlive-_W39Rj/kdenlive-16.08.2~ubuntu16.04.1/src/main.cpp:157
As I refused to let hours of editing go to waste, I started going over the project file editing out references by random until it finally opened without crashing. Here is the changes between my backup and the working file: 5365a5366,5381 > <tractor id="tractor0" in="0" out="541"> > <track producer="slowmotion:24:0,5:1:1" in="6224" out="6765"/> > <track producer="producer0"/> > <transition id="transition0"> > <property name="a_track">0</property> > <property name="b_track">1</property> > <property name="compositing">0</property> > <property name="distort">0</property> > <property name="mlt_service">qtblend</property> > <property name="always_active">1</property> > </transition> > </tractor> > <playlist id="overlay_track"> > <blank length="3491"/> > <entry producer="tractor0" in="0" out="541"/> > </playlist> 5376a5393 > <track hide="audio" producer="overlay_track"/>
The broken projects seem to open without crashing in Kdenlive 17.03.70 from the kdenlive-master ppa, so the problem appears to have been fixed.