Cannot run Qt Creator GUI outside of Qt. "The application was unable to start correctly (0xc000007b)" error

I downloaded C++ code from GitHub to tag images for training an object detector using Machine Learning.

Within Qt Creator 4.2.1 Based on Qt 5.8.0 (MSVC 2015, 32bit), I was able to compile and run the code. Unfortunately, I was not able to run the .exe outside of Qt Creator.

Initially, I received an error that

"The program can't start because libgcc_s_dw2-1.dll is missing". 

Thanks to QT The program can't start because libgcc_s_dw2-1.dll is missing, that was fixed easily by adding

"QMAKE_LFLAGS += -static" 

to the .pro file. Now, when I run it I get

"The application was unable to start correctly (0xc000007b). Click OK to close the application."  

I was able to reproduce the error using the simple "Hello World" default project that appears when you create a Qt Widget Application. This led me to believe something was wrong with my installation.

Based on the advice of this article: https://stackoverflow.com/questions/12099117/32-bit-qt-application-on-win-7-x64-wont-run-but-runs-fine-from-qt-creator, I used Dependency Walker to identify possible causes. I expected to see only a few items that I can follow up on. Instead, I received a list of close to 100 missing .dll files. All the files started with

"API-MS-WIN ###.DLL" or "EXT-MS ###.DLL" 

where ### represent some additional text characters, for example;

"API-MS-WIN-SHCORE-STREAM-WINRT-L1-1-0.DLL" 

I'm attaching a sample output.

Another suggestion was to copy over

libwinpthread-1.dll, libstdc++-6.dll, libgcc_s_dw2-1.dll.   

That did not work either.

My next move was to simply get the latest version of QT and wish for the best. I installed Qt Creator 4.8.1 Based on At 5.12.0 (MSVC 2015, 32 bit). This time, I could not even get the code to run in the IDE. I received 1000+ error messages!

Based on advice from several pages, I added

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets 

to the .pro file and it still would not compile.

Also, I verified that the application is being built as a 32bit application. I'm running on a 64 bit Windows 10 system.

If anyone would like to take a crack at it to see if they can create a working .exe, here is the link: github.com/clavicule/BBTag

Qt provides a tool to copy the necessary dlls to the folder of your executable.

The tools is called windeployqt.exe and comes with your Qt installation. For me it is located at C:\Qt\5.9.1\msvc2015_64\bin\windeployqt.exe. You will have to look at your installation path and probably the msvc_32 folder to find it.

Then you go to the folder with your executable in it, oben a command prompt or powershell and execute path\to\windeployqt.exe yourProgram.exe and it will automatically copy the necessary dll files to this folder. Afterwards you can run your program without issues.

The official documentation for the tool can be found here.

Alternative 1: While developing you could use QtCreator which automatically adds the paths to the dlls when running your program - make sure to include them if you deploy your program!

Alternative 2: Add the path to the necessary dlls to your PATH variable. This isn't recommended either, since everyone who gets your program would have to do the same to run it.