Hi, the same topic is addressed here (where you can also find some workaround and code snippets):

https://developer.vuforia.com/forum/unity-3-extension-technical-discussion/dataset-does-not-exist-error-when-using-unity-4-android

I have read the hole thread and my problem is not solved. I have post antother question becouse I don't have the same problem (DataSet don't loaded).

I have read also, from a moderator "We're looking into this issue to develop a solution and will update this thread once we know more." and I think the problem is not solved.

I don't know what to do now, I'm lost.

Ok. One question: what is the size of the Datasets (the .dat files) that you are using ?

If the Dataset is small, and the size of your APK primarily comes from large Unity assets that you are using (such as videos or large/complex 3D models),

then, one thing you may want to consider is to use AssetBundles to dynamically download the assets that you need into your application;

this would allow you to keep your APK small without having to deal with the OBB issue.

http://docs.unity3d.com/Documentation/Manual/AssetBundlesIntro.html

My .dat file is about 6,3Mb. And yes, my app has a lot of media files (Videos and images that grows the size to 800+Mb).

I'm going to try the AssetsBundle but I think it is a pity that I have done the apk and now I need to redoo all my project.

I'm gonna be killed, for sure :-(.

A reminder for devs using this method for extracting datasets from OBBs - be sure the enable write permissions in your Unity Build Settings.

You'll need to select Write Access = External (SDCard) from Player Settings > Other Settings > in the Configuration section. That will add the necessary permission to your manifest, enabling you to write the dataset files to the SDCard. Otherwise you'll get an error on that operation.

add this manualy 

    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

from editor doesnt work!!!

Vuforia 3.0.9 supports dataset loading from OBB expansion files;  procdure guidelines can be found here:

https://developer.vuforia.com/forum/faq/unity-how-can-i-handle-large-android-apps

@AlessandroB , 

We are using Unity3D 4.3.0f4 with Vuforia SDK 3-0-7. My Android application build size is 71MB. 

i have split the application and uploaded in ply store. application is downloaded successfully and open the camera mode. But There is no Augmentation.

I have seen the link which you given:

Vuforia 3.0.9 supports dataset loading from OBB expansion files;  procdure guidelines can be found here:

https://developer.vuforia.com/forum/faq/unity-how-can-i-handle-large-android-apps

Then what is the process for Vuforia SDK 3-0-7 ? 

Please can you help !!!

Then what is the process for Vuforia SDK 3-0-7 ? 

You should upgrade to 3.0.9.

Vuforia 3.0.9 is fully compatible with the previous 3.0.6 / 7 release, as it only contains some improvements and the added support for the OBB expansion files, which is precisely what you need.

So, your best guess would be to simply upgrade your App from 3.0.7 to 3.0.9 and apply the same process which is described in 

https://developer.vuforia.com/forum/faq/unity-how-can-i-handle-large-android-apps

i have solotion for this after a lot of reading and testing but not simple as it is

i uploaded my apps 117 MB and all works fine

if you need help upload your APK+OBB to https://mega.co.nz/  zip it all with password 12345 iwill fix it and will send you new link to https://mega.co.nz/ in order to download it no limit on the size email me at

with details i will provide solotion.