Activate the “SharePoint 2010 User Code Host” service.

Activate Sandbox Solutions

From SharePoint 2010 top-level site, logged in as a Site Collection Administrator do the following:

• Click Site Actions à Site Settings.
• Under Galleries, choose Solutions.
• Under the Solutions tab, click Upload Solution. Browse to .wsp package and click OK.
• Click the Activate button to activate the solution in the site collection. 

If the Activation Button is disabled we need to activate the “SharePoint 2010 User Code Host” service.

Activate “SharePoint 2010 User Code Host” service

Following are the steps to activate “SharePoint 2010 User Code Host” service:

1.       From Central Admin à Security à Configure Service Account

2.       select the Windows Service - Microsoft SharePoint Foundation Sandboxed Code Service option from the drop down and add the account which need to activate the service

3.       After configuring the service account for Sandbox, navigated to “Central Admin à Application Management à Manage Services”

4.       Start the service “Microsoft SharePoint Foundation Sandboxed Code Service”.

5.       Navigate to services and check for the service “SharePoint 2010 User Code Host” had started.