SYMPTOM:
When a user tries to open the Strategy Diagnostics and Performance Logging tool, the following error appears:

Error getting Intelligence Server instances Unexpected error occurred. Access is denied.

CAUSE:
The user does not have administrator privileges on the Intelligence Server machine running on a Windows operating system which is required in order to run the tool.
ACTION:
Grant Windows administrator privileges to the user or add the user to the administrator user group on the Windows machine.