"There's no Qt version assigned to this project for platform Win32" - visual studio plugin for Qt

Did you select a proper Qt version in the Qt settings of your project?

More detailed: If you right-click on the project there should be a "Qt Project Settings" option (or similar - I use the german version) near the end of the context menu. In there you can set the Qt version that this specific project uses. Is this one possibly not set correctly?

Solution:

1. Right click your project;
2. Qt Project Settings;
3. Under the Properties tab, you will find the option Version;
4. change it to a proper value;

Now, go ahead with your project.

Hope to help

Open vcxproj file in a notepad, look for QtVersion...something=... Ensure that the version value is really 4.8.0 (or whatever is your actual QT SDK version).