Blackbaud Sphere allows users to save report criteria to be run again. If a user receives the error message, "Error: An Unexpected Error has Occurred" when running a saved report, this solution outlines the steps needed to resolve the error message.
Try recreating the saved report. Your report may reference fields that are no longer available in Sphere.
If that does not do it please let us know. Contact Support and reference this article.
In the case, please include the name of the report that is generating the error message as well as the last time the report ran without generating an error message.