This happens when a modern Qt 5 DLL is in your PATH before Qt 4.8.7. Fix: Reorder your system environment variables so the Qt 4.8.7 bin folder appears first.
If you are searching for a reliable , you have likely encountered a problem: The Qt Company has officially moved all legacy versions to an "archive" status, making them harder to find via the default online installer. This guide will provide step-by-step instructions, security considerations, and alternative sources to get Qt 4.8.7 up and running on modern operating systems. qt 4.8.7 download
tar -xzvf qt-everywhere-opensource-src-4.8.7.tar.gz cd qt-everywhere-opensource-src-4.8.7 This happens when a modern Qt 5 DLL
In this directory, you will find the source packages ( .tar.gz and .zip ). This is the raw code. If you are on Linux, this is usually what you want. If you are on Windows and looking for pre-built binaries (libraries already compiled for MSVC or MinGW), you need to look for a specific subfolder often labeled qt-opensource-windows-x86-vs2010-4.8.7.exe or similar variations depending on the compiler. If you are on Linux, this is usually what you want
Unlike modern Qt versions, which are easily accessible via the online installer, locating a legitimate requires looking in specific archives. The standard Qt Maintenance Tool no longer offers these legacy versions by default.