Clint-525719 (8/29/2016)
I have searched for an answer on this, but I am having trouble finding anything. I have created a Windows account that I will use as the Data Source login on the SQL Server containing the data to be retrieved. However, the only way I can make the connection work is if that same Windows account is an administrator on the SSRS box (not a sysadmin, but in the Windows administrator group). I don't want to give full admin permissions if I can avoid it. Thoughts?Thanks!
It doesn't need to be an administrator but it needs the rights to Log On Locally - that's probably the part that bit you.
There is some information on this approach in the Stored Credentials section of this doc:
Specify Credential and Connection Information for Report Data Sources
https://msdn.microsoft.com/en-us/library/ms160330.aspx
Sue