ERROR 010096: There is no Spatial Analyst license currently available or enabled

Error Message

Using a Spatial Analyst tool, such as 'Hillshade', returns a Tool Not Licensed dialog box with the following error message:

Unable to execute the selected tool. 

You do not have the necessary license to execute the selected tool. 
ERROR 010096: There is no Spatial Analyst license currently available or enabled.

Cause

• The Spatial Analyst extension is not authorized.
• The Spatial Analyst extension is not enabled in ArcMap.
• The Spatial Analyst extension is not enabled in ArcCatalog.

Solution or Workaround

Perform the solutions below in the order they are presented.

Note:
These solutions assume the Spatial Analyst license has been purchased, but not enabled. Refer to ArcGIS Spatial Analyst for more information.

Verify that the Spatial Analyst extension is authorized

1. Navigate to Start > All Programs > ArcGIS. Launch ArcGIS Administrator.
2. Click Availability in the left pane.
3. Ensure the extension is authorized for Single Use licenses, or Available for Concurrent Use licenses. If the licenses are not authorized, refer to ArcMap: Authorizing your software for more information.

Enable the extension in ArcMap

1. Launch ArcMap.
2. Navigate to Customize > Extensions, and check the Spatial Analyst checkbox. This enables the extension in ArcMap.

Enable the extension in ArcCatalog

1. Launch ArcCatalog.
2. Navigate to Customize > Extensions, and check the Spatial Analyst checkbox. This enables the extension in ArcCatalog.

Note:
Certain functionalities in ArcMap, such as ModelBuilder, require the extension enabled in ArcCatalog.