Cannot access "Diagnostics" panels within Configuration Centre (Center)

Problem

On clicking the "Diagnostics" button on a web application in Configuration Centre you see an error message, most commonly:

"Index was out of range. Must be non-negative and less than the size of the collection."

Note that the error message and how it displays can vary.

Cause

This can occur on an installation upgraded from older versions of Service Desk.  It is a known issue logged as Problem 5913 to be fixed in a future release.  If you experience this issue please contact your local support team to have your instance attached to the the problem record.

Solution

Perform the following steps to resolve the issue:

1. On each Service Desk server extract the attached ZIP file to a local disk.
2. Run the extracted ServiceDesk.FixDiagnostics.exe application as an administrator.

Please contact any errors reported by the application to your local support team.

Environment

This issue can occur on Service Desk 7.7.1 onwards.