The permissions granted to user 'NT AUTHORITY\IUSR' are insufficient for performing this operation. SharePoint 2010

The permissions granted to user 'NT AUTHORITY\IUSR' are insufficient for performing this operation. SharePoint 2010

We got this issue when we try to launch SSRS Reports on Anonymous SharePoint2010 site. When we try to access the report we are getting error as "This operation is not possible as IUser doesn't have permissions. After several hours of trying to figure this one out, I finally did. So, for anyone who may come across this same issue, here is the answer.

This is where, and how, I found the IUSR.

·         First, let me explain that open IIS Manager and select Web Site which we have made Anonymous and selected 'Edit Permissions’ on top right corner.

·         Click on the 'Security' tab à 'Edit' (under groups and users) à 'Add' (under groups and users). This brings you to the 'Select Users, Computers, Service Accounts, or Groups' window.

·         Click on the 'Object Types...' button and just select everything and hit 'OK'.

·         Next, click on 'Locations ...' and select the parent-most option (this will most likely be the server itself) and hit 'OK'

·         Next, click on the 'Advanced' button and select the 'Find Now' button.

·         You will see several search results. Within this list, you will find the IUSR username. Select it, and hit 'OK' and grant him FULL permissions.

.     Go to IIS and select your site-->Authentication and then select "Anonymous Authentication".
      Click "Edit" at top right hand side, from the popup menu select "Application Pool Identity" radio button and Click OK.

And there you have it.

Happy SharePointing !!!