This is the gold standard for professionals:
Do not rely on the online installer for critical infrastructure. Use aqtinstall to download the entire Qt 5.15.2 source and binaries once. Archive that folder on your company network drive. You will thank yourself two years from now when the online installer has deprecated 5.15. Do you still use Qt 5.15 in production? Or have you moved to Qt 6? Let me know in the comments below. qt 5.15 offline installer
But why all the fuss? And why should you care about an offline installer in an era of fast internet? This is the gold standard for professionals: Do
# Install aqtinstall pip install aqtinstall aqt install -O ./qt_offline_folder 5.15.2 windows desktop win64_msvc2019_64 That's it! You can now zip that folder, copy it to any machine, and set the PATH. You will thank yourself two years from now