Thanks for your response guys!

The traceback in debugger was not very helpful. The real application is 20+ million lines of code, but I just extracted conceptual code. Didn't really try to create a small test program, but the issue has been resolved.

There was a 100 ms timer that would scroll the list of items to the far right automatically after the new list of items were populated. Randomly, this feature would cause the crash. See callstack below.

Qt Code: 
  1. STACK ? 6 ? 0x64f55329 QListView::updateGeometries
  2. STACK ? 7 ? 0x64f4d3d7 QListView::indexAt
  3. STACK ? 8 ? 0x64f32568 QAbstractItemView::horizontalScrollbarValueChanged
  4. STACK ? 9 ? 0x6a5a7110 QMetaObject::activate
  5. STACK ? 10 ? 0x6504ab10 QAbstractSlider::valueChanged
  6. STACK ? 11 ? 0x64e0fdb9 QAbstractSlider::setValue
  7. STACK ? 12 ? 0x64e0fb42 QAbstractSlider::setRange
  8. STACK ? 13 ? 0x64f54c74 QListView::updateGeometries
  9. STACK ? 14 ? 0x64f303a1 QAbstractItemView::doItemsLayout
  10. STACK ? 15 ? 0x64f4a2b9 QListView::doItemsLayout
  11. STACK ? 16 ? 0x64f396ee QAbstractItemView::timerEvent
  12. STACK ? 17 ? 0x6a5aa5ec QObject::event
  13. STACK ? 18 ? 0x64b2e913 QWidget::event
  14. STACK ? 19 ? 0x64e4ac97 QFrame::event
  15. STACK ? 20 ? 0x64eba1a4 QAbstractScrollArea::event
  16. STACK ? 21 ? 0x64af1a36 QApplicationPrivate::notify_helper
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Well, just by changing the horizontal scrollbar policy to always visible instead of automatic on the QListWidget solved this issue!

This is on Qt 4.8.2 on Windows x64 MSVS 2012