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Failed to load QCARWrapper.dll

June 10, 2015 - 3:10am #1

Vuforia SDK Version: vuforia-unity-mobile-android-ios-4-2-3.unitypackage -

Description with steps to reproduce:

This is the situation:

- USB WebCam plug and play.

- Unity 5.02f1 (32bit).

- new project

- in Hierarchy only Directional Light and ARCamera

- select ARCamera and in Inspector>Web Cam Behaviour (Script)  there is this red error: "An error occured while trying to enable Vuforia play mode"

- in Console there is this error:  Failed to load 'Assets/Plugins/QCARWrapper.dll' with error 'Impossibile trovare il modulo specificato.

', GetDllDirectory returned ''. If GetDllDirectory returned non empty path, check that you're using SetDirectoryDll correctly.


The web cam is operating normally in windows but in unity in Play Mode not.

In the ... /Assets/Plugins the QCARWrapper.dll file is present.


Can you help me,please?

(sorry my English is not good.)



Development OS (Mac OS X, Windows, Linux): Windows XP SP2 -

Mobile OS and Version: Android 2.3.6 -

Mobile Device Manufacturer and Model name: Samsung Galaxi mini 2 GTS6500 -

Do the Vuforia Sample Applications show the same behavior?: yes

Failed to load QCARWrapper.dll

August 9, 2016 - 3:23pm #9

Vuforia 6 introduces support for Windows 64-bit Unity Editor. Please see our announcement for more details.

Failed to load QCARWrapper.dll

May 10, 2016 - 8:34am #8

Vuforia 5.0 supports the 32bit version of the Unity Editor on Windows, and the 64bit version on Mac.

So, There are two possible solutions:

  1. you just need to install and use the Unity 5 32bit Editor, on Windows.


  1. Create a new folder "x86" inside


    inside your unity project structure Then move the following files from "Plugins" to newely created"x86" folder.

    • QCARWrapper.lib
    • QCARWrapper.dll
    • QCARWrapper.dll.signature
    • QCARWrapper.exp

After that check log message, If you see the log like:

Setting platform to 'Editor' for plugin: Assets/Plugins/x86/VuforiaWrapper.dll
Vuforia.EditorClasses.ExtensionImport:UpdatePluginSettings() (at Assets/Vuforia/Editor/Scripts/ExtensionImport.cs:43)

Then , Congrats !! You are ready to Go!

Failed to load QCARWrapper.dll

October 9, 2015 - 11:46am #7

To be clear:

you can use your Windows 64bit OS;

it's just that you need to download the 32bit Editor of Unity 5 (this will work perfectly on your Win 64bit OS installed on your PC).


Failed to load QCARWrapper.dll

October 9, 2015 - 9:03am #6

Thanks for help me so fast!!!

I think I have a windows 64 bit to kill :P

Kind regards.

Failed to load QCARWrapper.dll

October 9, 2015 - 7:20am #5


the screenshot image you attached shows the following message:

"...QCARWrapper.dll: expected 64bit architecture..."

This is likely due to using Unity 5 64bit on Windows.

Vuforia 5.0 supports the 32bit version of the Unity Editor on Windows, and the 64bit version on Mac; 

so, you just need to install and use the Unity 5 32bit Editor, on Windows.


Failed to load QCARWrapper.dll

October 9, 2015 - 7:00am #4


I have the same problem. You had succes to fix the problem? I attach a photo of this problem.


Image icon errorUnity.PNG195.93 KB

Failed to load QCARWrapper.dll

June 14, 2015 - 11:49am #3

Windows XP has reached end of life several months ago, after 12 years of life, as mentioned in the Microsoft website:

Maybe time to upgrade ?


Failed to load QCARWrapper.dll

June 11, 2015 - 3:54am #2

I installed Unity 5.02f1 and Vuforia 4.2.3 in another PC (also in Windows XP but SP3 not SP2) but the problem persists.

I enclose screen shot of the problem.

I can not understand where I'm wrong...



Image icon Error 01.JPG193.38 KB
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