VS2010 Issue. Project in 64 bit mode won't find Qt version, setting Qt Version reverts project to Win32.

Geeklat

This is a really strange issue I've been hammering at for a bit. Attempting to set up the project on a 64-bit Win7 machine. This issue occurs in all Qt projects including a brand new project.

I set the project as a x64 project. When I go to build I get the following error:
"WARNING: Can't find the Qt version that's associated with this project. Defaulting to 4.7.2 instead. Please assign a valid Qt version to this project in the Qt project settings."

I then go into Qt>Qt Project Settings and notice that the "Version" is blank. I then set it to Qt 4.7.2 (my current version). Upon doing this and clicking 'Ok' my project is reverted to run in a Win32 format. Is there a way to get around this? I've tried re-installing and rebuilding everything multiple times.

ludde

So you have two different Qt installations, both 4.7.2, but one for 32 bit and the other for 64 bit?
And when you tell it to use the 64 bit installation, it uses the 32 bit installation?

Geeklat

I only had a 64x bit installation configured, but it was finding 32 bit stuff and only 32 bit stuff. Tried uninstalling/reinstalling. Tried deleting all remnants and Qt directories. The eventual fix was to take a set up that was working on a different machine and replace my setup's libraries and various files with their version and now it seems to be working.

tobias.hunger

We check the Qt Core library itself for the word with (starting with Qt Creator 2.2 that is), so if creator says it is a 32bit binary it most likely is. Would have been interesting to examine your broken setup... is there any chance that you still have the QtCore.dll around in backups, etc. somewhere?

cbarnes

I don't know if you have solved this problem. I was having the exact same issue and I found a work around. However it requires having Visual Studio 2008 as well as VS 2010. My work around is this:

Create a new Qt Application Project
Create a X64 configuration for the project and set it as active
Attempt to build it and you will get one or more:
WARNING: Can't find the Qt version that's associated with this project. Defaulting to Qt 4.7.1 instead. Please assign a valid Qt version to this project in the Qt project settings.
Try to set this with: Right Click->Qt Project Settings

It will always switch back to a 32 bit build no matter what you do.

Now the fun part: edit test.vcproj look for the entry:

<Global
Name="QtVersion Win32"
Value="Qt 4.7.1 64Bit"
/> -- this will be name what ever you defined it as

and DELETE IT.

Save the project file.
Reload the project file into the solution. It should detect the change and ask you to reload.
Now <Right Click> -> Qt Project Settings has changed to "change project's Qt Version".
Set the correct Qt Version (in my case Qt 4.7.1 64Bit).
Now you can build it. Optionally import it into Visual Studio 2010