Qt Reference Documentation

Known Issues

An up-to-date list of known issues can be found at Qt Bug Tracker.

For a list list of known bugs, see the Task Tracker at the Qt website.

An overview of known issues may also be found at: Known Issues Wiki.

Installation Issues

Installing the Source Package on Unix systems

  • If you download a Zip source package, you will need to convert Windows-style line endings (CR/LF) to Unix-style line-endings (LF) when you uncompress the package. To do this, give the "-a" option when you run the "unzip' command.
  • If you fail to supply the "-a" option when unzipping the package, you will see the following error message when you attempt to execute the configure command: "bash: ./configure: /bin/sh^M: bad interpreter: No such file or directory"

Installing on Mac OS X 10.6 "Snow Leopard"

  • Performing a new install of the Qt 4.6 beta on Snow Leopard triggers a bug in the installer that causes the install to fail. Updating an existing Qt installation works fine.
  • There are two workarounds, either disable spotlight for the target drive during the install, or do a custom install where you deselect documentation and examples. Run the installer again as a full install to get the documentation and examples installed.

Issues with Third Party Software


  • There is a bug in the 169.xx NVIDIA drivers on certain GeForce 8 series cards that is triggered by the OpenGL paint engine when using QPainter on a QGLWidget to draw paths and polygons. Some other painting operations that end up in the path fallback are affected as well. The bug causes the whole X server to repeatedly hang for several seconds at a time.
  • There is an issue with NVIDIA's 9xxx driver series on X11 that causes a crash in cases where there are several QGLContexts and the extended composition modes are used (the composition modes between and including QPainter::CompositionMode_Multiply and QPainter::CompositionMode_Exclusion). This affects the composition mode demo in Qt 4.5, for example. The crash does not occur in newer versions of the drivers.


  • When using version of the NVIDIA drivers for the GeForce 6600 GT under Windows XP, Qt applications which use drag and drop will display reduced size drag and drop icons when run alongside applications that use OpenGL. This problem can be worked around by reducing the level of graphics acceleration provided by the driver, or by disabling hardware acceleration completely.
  • With NVIDIA GeForce 7950 GT (driver version, a fullscreen QGLWidget flickers when child widgets are shown/hidden. The workaround for this is to use setGeometry() with a width/height 1 pixel bigger than your geometry and call show().
  • A bug in the Firebird database can cause an application to crash when fbembed.dll is unloaded. The bug is fixed in version 2.5.
  • On Windows 7, resizing windows is slower than on Vista/Xp. This is because the gesture initialization process (required for native gesture support) currently calls winId() on widgets, which causes whole widget hierarchies to use native window handles. This slows down resizing.
  • Compile errors with Intel C++ Compiler.
    There seems to be a bug in the Intel compiler with respect to over-agressive inlining of code. The problem will manifest itself during the link phase of QtGui where it fails with the error that it cannot find QObjectData::~QObjectData(). See http://bugreports.qt.nokia.com/browse/QTBUG-5145 for updates on this bug. Also, due to some bugs in WebKit, the QtScript and QtWebKit modules will not compile. See http://bugreports.qt.nokia.com/browse/QTBUG-6297 for a workaround for QtScript.
  • Compile errors with Microsoft Visual C++ compiler.
    There seems to be a bug in the Microsoft compiler when compiling with O2 optimization level in 64 bit. This problem will result in crashes in QAbstractItemView::viewOptions(). See http://bugreports.qt.nokia.com/browse/QTBUG-11445 for updates on this bug.

Mac OS X

  • If a sheet is opened for a given window, clicking the title bar of that window will cause it to flash. This behavior has been reported to Apple (bug number 5827676).



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