Windows 7, 64 bit, DLL problems

This problem is related to missing the Visual Studio "redistributable package." It is not obvious which one is missing based on the dependency walk, but I would try the one that corresponds with your compiler version first and see if things run properly:

Visual Studio 2015

Visual Studio 2013

Visual Studio 2010

Visual Studio 2008

I ran into this problem because I am using the Visual Studio compilers, but not the full Visual Studio environment.


Going to dare to inject a new link here: The latest supported Visual C++ downloads. Stein Åsmul, 29.11.2018.


I just resolved the same problem with C++ Qt 5 and Windows 7 64 bits with MSCVC 2012.

In the beginning I thought it was a MSVC/Windows DLL file problem, but as BorisP said, the problem was in my project dependencies. The key is "How to know your project dependencies in Qt 5?".

As I didn't find any clear way to know it (Dependency Walker didn't help me a lot...), I followed next the "inverse procedure" that takes no more than 5 minutes and avoid a lot of headaches with DLL file dependencies:

  1. Compile your project and take the executable file to an empty folder: myproject.exe
  2. Try to execute it, It will retrieve an error (missing DLL files...).
  3. Now, copy all the DLL files from Qt (in my case they were in C:\Qt\Qt5.1.1\5.1.1\msvc2012_64_opengl\bin) to this folder.
  4. Try to execute again, it will probably works fine.
  5. Start to delete progressively and try every time your executable still works, trying to leave the minimum necessary DLL files.

When you have all the DLL files in the same folder it is easier to find which of them are not valid (XML, WebKit, ... whatever..), and consequently this method doesn't take more than five minutes.


I just resolved the same problem.

Dependency Walker is misleading in this case and caused me to lose time. So, the list of "missing" DLL files from the first post is not helpful, and you can probably ignore it.

The solution is to find which references your project is calling and check if they are really installed on the server.

@Ben Brammer, it is not important which three .ocx files are missing, because they are missing only for Leo T Abraham's project. Your project probably calls other DLL files.

In my case, it was not three .ocx files, but missing MySQL connector DLL file. After installing of MySQL Connector for .NET on server, the problem disappeared.

So, in short, the solution is: check if all your project references are there.