I want to remove the installed Qt 4.8 libraries and install Qt 4.6 libraries on my mac.
But when I try to install them I get:
"Qt libraries cannot be installed on this disk. A newer version of this software already exists on this disk"
I removed the /usr/local/Qt4.8.x folder from the disk but the message is still here.
How can I remove the old libraries?
You shouldn't manually delete a folder unless there is no other option. You should try running the uninstall script first:
sudo python /Developer/Tools/uninstall-qt.py
The path to this script will be different if you are running the latest Xcode app bundle and not the default Snow Leopard/Lion Xcode.
来源：https://stackoverflow.com/questions/13103017/remove-qt-libraries-on-mac