Updated from Qt4 to Qt5 -> QtCore4.dll is missing

erenthesun

Hey,

i was using Qt4 for a while and now updated to using Qt5, but my application won't start, saying:

"The program can't start because QtCore4.dll is missing from your computer. Try reinstalling the program to fix this problem."

I'm using the Qt5 Visual-Studio Add-In
my Qt-folder is located at C:\qt\5.0.2
in Visual-Studio Qt-Options: QT_5.0.2, C:\qt\5.0.2\qtbase
project's Qt-Version is QT_5.0.2
i added the user environment variable QT_DIR with key C:\qt\5.0.2
in project settings i added "additional include directories":

$(QT_DIR)\qtbase\include\QtCore
$(QT_DIR)\qtbase\include\QtGui
$(QT_DIR)\qtbase\include\QtXml
$(QT_DIR)\qtbase\include\QtOpenGL
$(QT_DIR)\qtbase\include\QtWidgets
and also $(QT_DIR)\qtbase\include

in project settings i added "additional library directories":

$(QT_DIR)\qtbase\lib

in project settings i added "additional dependencies":

Qt5Core.lib
Qt5Gui.lib
Qt5Xml.lib
Qt5OpenGL.lib
Qt5Test.lib
Qt5Widgets.lib
qtmain.lib
Qt5PlatformSupport.lib

I have no idea, why it still keeps asking for the QtCore4.dll. Can anybody help?

JKSH

Did you:

Clean your build tree, and

Recompile your project?

Uninstalling Qt 4 before doing that could also help

rb58

Here is my solution what worked for me so far: I opened up the Task Manager, clicked on "Start Up", and simply chose "disable Daemon". Since then I don't see this annoying pop-up message! :-)

frankiefrank

Is it possible that in your application you are using some third party dll compiled with a previous version of Qt? Something like Qwt or Scintilla?

My suggestion is using DependencyWalker (http://www.dependencywalker.com/). If you run it and load the compiled executable it should be rather easy to see where the Qt 4 core dll is referenced.

oops I see now that this is an old post :)