cannot collect keys

This is the official solution (by activision forum):

support.activision.com/.../Cannot-Access-MW3-after-Collection-4-Download

If you've downloaded DLC Collection 4 and cannot access Modern Warfare 3, please follow these steps:

From the Xbox LIVE Dashboard, go to Settings and select System

Select Storage

Select Hard Drive

Select Games and Apps

Select Modern Warfare 3

Find and select "Collection 4: Final Assault Marketplace Content"

Select Delete

Launch Modern Warfare 3 and you should now be able to access the Collection 4 content

This will delete a key that is required to download DLC Collection 4, but will not delete the content. The key can be re-downloaded from the Xbox LIVE Marketplace if you need to re-download all of the DLC Collection 4 content at a later date.

havent done this myself, but found it on activision

From the Xbox From the Xbox LIVE Dashboard, go to Settings and select System

Select Storage

Select Hard Drive

Select Games and Apps

Select Modern Warfare 3

Find and select "Collection 4: Final Assault Marketplace Content"

Select Delete

Launch Modern Warfare 3 and you should now be able to access the Collection 4 content

This will delete a key that is required to download DLC Collection 4, but will not delete the content. The key can be re-downloaded from the Xbox LIVE Marketplace if you need to re-download all of the DLC Collection 4 content at a later date.

support.activision.com/.../Cannot-Access-MW3-after-Collect ion-4-Download

Now I'm really stuck. Tried deleting from registry everything Microsoft Solitaire Collection and get the infamous:

Cannot delete Microsoft.MicrosoftSolitaireCollection_3.5.11021.0_x64_8wekyb3d8bbwe: Error while deleting key.

Hello THE CON OF M4N

We are aware some customers cannot access MW3 after downloading the Collection 4 DLC on Xbox 360. If you cannot access MW3 after downloading the content, click
here.

[table][tr][td]If you've downloaded DLC Collection 4 and cannot access Modern Warfare 3, please follow these steps:

1. From the Xbox LIVE Dashboard, go to Settings and select System
2. Select Storage
3. Select Hard Drive
4. Select Games and Apps
5. Select Modern Warfare 3
6. Find and select "Collection 4: Final Assault Marketplace Content"
7. Select Delete
8. Launch Modern Warfare 3 and you should now be able to access the Collection 4 content

This will delete a key that is required to download DLC Collection 4, but will not delete the content. The key can be re-downloaded from the Xbox LIVE Marketplace if you need to re-download all of the DLC Collection 4 content at a later date.[/td][/tr][/table]

Activision Support

Hello RYDERBROS1315

If you've downloaded DLC Collection 4 and cannot access Modern Warfare 3, please follow these steps:

From the Xbox LIVE Dashboard, go to Settings and select System

Select Storage

Select Hard Drive

Select Games and Apps

Select Modern Warfare 3

Find and select "Collection 4: Final Assault Marketplace Content"

Select Delete

Launch Modern Warfare 3 and you should now be able to access the Collection 4 content

This will delete a key that is required to download DLC Collection 4, but will not delete the content. The key can be re-downloaded from the Xbox LIVE Marketplace if you need to re-download all of the DLC Collection 4 content at a later date.

Source: Activision Support