Symptoms: A document library or Report library was created within a site on SharePoint 2010 and an excel document was uploaded. Once the file was uploaded , upon clicking on the excel document , an error is displayed saying the workbook cannot be opened as shown below

The reason behind this is usually due to the following:-

  1. For excel services and to open the excel document within the browser make sure you have the following Hotfix installed: Windows6.1-KB976462-v2-x64.msu available here.
  2. Or it could be because you use a custom Service Account for all your service application / Excel Services then you need to do either one of the following :
  • Add the Service account to be a Dbowner on your content database that holds the web application
  • Or copy the following script and run it
Add-PSSnapin Microsoft.SharePoint.PowerShell -EA 0
$webApp = Get-SPWebApplication "REPLACE_NAME_OF_WEBAPP"