PowerView in SharePoint Server

Step 1: Go to the Microsoft SQL Server 2012, click Configuration Tools, and then click the PowerPivot for SharePoint 2013 Configuration

configure the next step based on the following link.

http://rajeshagadi.blogspot.in/2013/07/installing-powerpivot-for-sharepoint.html

Step 2: In Sharepoint, Navigate to site collection and Click Settings.
In the Site Collection Administration group Click Site Collection Features.
Find Power View Integration Feature and PerformancePoint Service Site Collection Feature in the list.
Click Activate. The feature status will change to Active.

Sometime following error occurred  in the Excel service:

Error 1:

The following data connection file does not exist or you do not have permissions to it: 

 The following connections failed to refresh: 

Solution

Change Connection String in Report files.

Error 2:

An error occurred while accessing Secure Store Service. The following connections failed to refresh

Solution:

IIS Reset

Error 3: An error occurred while loading the model for the item or data source 'EntityDataSource'. Verify that the connection information is correct and that you have permissions to access the data source.

Solution:
Restart the following service:
SQL Server (MSSQLSERVER)
SQL Server (POWERPIVOT)
SQL Server Agent (MSSQLSERVER)
SQL Server Agent (POWERPIVOT)
SQL Server Analysis Services (MSSQLSERVER)
SQL Server Analysis Services (POWERPIVOT)
and

IIS Reset

Error 3: We're sorry. We ran into a problem completing your request.

Please try that again in a few minutes.

Solution:

IIS Reset or System Restart
http://algrandi.azurewebsites.net/index.php/excel-services-application-crashes-sp-20102013/