I have just installed QGIS 3.2 on my Mac (over the top of 3.0.2) but it keeps crashing on start up -- before opening any window but after the splash screen is removed.
I have installed Python 3.6.6 and Qt 5.11.0 in the process of trying to fix this.
Update: I have now logged this as an issue on the bug tracker here.
I have appended a truncated crash report as it would have been sent to Apple. Quick summary is that the stack trace shows it dying from a segfault in Thread 0 which appeared to be trying to set the Title bar text.:
Process: QGIS [90674] Path: /Applications/QGIS3.app/Contents/MacOS/QGIS Identifier: org.qgis.qgis3 Version: 3.2.0 (3.2.0 [exported]) Code Type: X86-64 (Native) Parent Process: ??? [1] Responsible: QGIS [90674] User ID: 501 Date/Time: 2018-07-02 16:33:21.596 +1200 OS Version: Mac OS X 10.13.5 (17F77) Report Version: 12 Anonymous UUID: BE9EB719-113B-804E-96AC-C6D8FB029D02 Time Awake Since Boot: 14000 seconds System Integrity Protection: enabled Crashed Thread: 0 Dispatch queue: com.apple.main-thread Exception Type: EXC_BAD_ACCESS (SIGSEGV) Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000008 Exception Note: EXC_CORPSE_NOTIFY Termination Signal: Segmentation fault: 11 Termination Reason: Namespace SIGNAL, Code 0xb Terminating Process: exc handler [0] VM Regions Near 0x8: --> __TEXT 0000000100bf1000-0000000101055000 [ 4496K] r-x/rwx SM=COW /Applications/QGIS3.app/Contents/MacOS/QGIS Thread 0 Crashed:: Dispatch queue: com.apple.main-thread 0 org.qt-project.QtWidgets 0x0000000105fdb3ed QAction::setText(QString const&) + 13 1 libqgis_app.3.2.0.dylib 0x00000001010fc641 QgisApp::changeEvent(QEvent*) + 89 2 org.qt-project.QtWidgets 0x000000010601e790 QWidget::event(QEvent*) + 144 3 org.qt-project.QtWidgets 0x000000010613e514 QMainWindow::event(QEvent*) + 1108 4 libqgis_app.3.2.0.dylib 0x00000001010b34f5 QgisApp::event(QEvent*) + 249 5 org.qt-project.QtWidgets 0x0000000105fe5792 QApplicationPrivate::notify_helper(QObject*, QEvent*) + 306 6 org.qt-project.QtWidgets 0x0000000105fe6aaf QApplication::notify(QObject*, QEvent*) + 383 7 org.qgis.qgis3_core 0x0000000102ec98b7 QgsApplication::notify(QObject*, QEvent*) + 93 8 org.qt-project.QtCore 0x00000001096bd32f QCoreApplication::notifyInternal2(QObject*, QEvent*) + 159 9 org.qt-project.QtWidgets 0x0000000106019ca2 QWidget::setWindowTitle(QString const&) + 482 10 libqgis_app.3.2.0.dylib 0x00000001010e55a0 setTitleBarText_(QWidget&) + 1315 11 org.qt-project.QtCore 0x00000001096edcdb QMetaObject::activate(QObject*, int, int, void**) + 2347 12 org.qgis.qgis3_core 0x000000010352ee92 QgsProject::isDirtyChanged(bool) + 64 13 org.qgis.qgis3_core 0x000000010307fa83 QgsProject::setSnappingConfig(QgsSnappingConfig const&) + 141 14 libqgis_app.3.2.0.dylib 0x0000000101253cb2 QgsSnappingWidget::QgsSnappingWidget(QgsProject*, QgsMapCanvas*, QWidget*) + 11058 15 libqgis_app.3.2.0.dylib 0x000000010109e3fd QgisApp::createToolBars() + 407 16 libqgis_app.3.2.0.dylib 0x0000000101096b8a QgisApp::functionProfile(void (QgisApp::*)(), QgisApp*, QString const&) + 62 17 libqgis_app.3.2.0.dylib 0x00000001010773be QgisApp::QgisApp(QSplashScreen*, bool, bool, QString const&, QString const&, QWidget*, QFlags) + 10652 18 org.qgis.qgis3 0x0000000100c032d4 main + 20280 19 libdyld.dylib 0x00007fff7116f015 start + 1 [ snip ] Logical CPU: 2 Error Code: 0x00000004 Trap Number: 14 Binary Images: 0x100bf1000 - 0x101054fff +org.qgis.qgis3 (3.2.0 - 3.2.0 [exported]) /Applications/QGIS3.app/Contents/MacOS/QGIS 0x101061000 - 0x101064fff +org.qgis.qgis2_native (3.2.0 - qgis_native 3.2.0) /Applications/QGIS3.app/Contents/Frameworks/qgis_native.framework/Versions/3.2/qgis_native 0x101067000 - 0x1017f4ffb +libqgis_app.3.2.0.dylib (0) /Applications/QGIS3.app/Contents/MacOS/lib/libqgis_app.3.2.0.dylib 0x101b72000 - 0x101c2cff3 +libqwt.dylib (0) /Applications/QGIS3.app/Contents/MacOS/lib/libqwt.dylib 0x101c95000 - 0x101cdaff3 +org.qgis.qgis3_3d (3.2.0 - qgis_3d 3.2.0) /Applications/QGIS3.app/Contents/Frameworks/qgis_3d.framework/Versions/3.2/qgis_3d 0x101d0c000 - 0x101d2fffb +org.qt-project.QtSql (5.9 - 5.9.3) /Applications/QGIS3.app/Contents/Frameworks/QtSql.framework/Versions/5/QtSql 0x101d42000 - 0x101d46ffb +org.qt-project.QtConcurrent (5.9 - 5.9.3) /Applications/QGIS3.app/Contents/Frameworks/QtConcurrent.framework/Versions/5/QtConcurrent [snip] External Modification Summary: Calls made by other processes targeting this process: task_for_pid: 5 thread_create: 0 thread_set_state: 0 Calls made by this process: task_for_pid: 0 thread_create: 0 thread_set_state: 0 Calls made by all processes on this machine: task_for_pid: 888798 thread_create: 0 thread_set_state: 0 VM Region Summary: ReadOnly portion of Libraries: Total=495.8M resident=0K(0%) swapped_out_or_unallocated=495.8M(100%) Writable regions: Total=203.8M written=0K(0%) resident=0K(0%) swapped_out=0K(0%) unallocated=203.8M(100%) VIRTUAL REGION REGION TYPE SIZE COUNT (non-coalesced) =========== ======= ======= Accelerate framework 256K 2 Activity Tracing 256K 2 CG backing stores 2876K 5 CG image 80K 4 CoreAnimation 20K 4 CoreGraphics 8K 2 CoreImage 8K 3 CoreUI image data 472K 7 CoreUI image file 180K 3 Foundation 4K 2 Kernel Alloc Once 8K 2 MALLOC 185.6M 50 MALLOC guard page 48K 11 Memory Tag 242 12K 2 STACK GUARD 56.0M 11 Stack 12.6M 11 VM_ALLOCATE 160K 15 __DATA 32.5M 348 __FONT_DATA 4K 2 __LINKEDIT 230.1M 104 __TEXT 265.7M 339 __UNICODE 560K 2 mapped file 50.2M 23 shared memory 632K 11 =========== ======= ======= TOTAL 838.1M 941