While deploying qt in windows, the official docs recommend using windeployqt.exe

However, once the outputs of windeployqt.exe are packaged and executed in a different machine without any qt installments, I encountered “msising libgcc_s_seh-1.dll” error.

Solution

When I ran windeployqt.exe, I just ran it from powershell.

When I used the Qt 5.12.6(MinGW 7.3 64-bit) terminal, and executed windeployqt.exe the same way as I did before, the outputs were different, and this time it had copied “libgcc_s_seh-1.dll” to the output directory.

After packaging this output and running in a different machine, the executable ran okay without errors.

So the solution is to run windeployqt.exe from the QT’s mingw terminal that is installed in your computer.