Can't start a Program because Qt5Cored.dll is missing

The file Qt5Cored.dll will exist on your system, otherwise it would not work from Qt Creator either. I think it's just Windows search that lets you down. Open a cmd prompt and do a dir c:\Qt5Cored.dll /s

Another note is that those *d.dll are debug DLL's, which means you are distributing a debug version of your application. You might want to build a release version for distribution instead. (In which case you'll need Qt5Core.dll)

On my computer the Qt5Core.dll and other .dll files are stored here C:\Qt\Qt5.9.1\5.9.1\xxx\bin (where xxx is the compiler version). Your Qt version may differ.

Copy the .dll files you want to the application location (where your .exe file is). These are the minimum .dll files I needed to copy for my basic app to work:

• libgcc_s_dw2-1.dll
• libstdc++-6.dll
• libwinpthread-1.dll
• Qt5Core.dll
• Qt5Gui.dll
• Qt5Widgets.dll