As part of of the upgrade process, an opportunity to upgrade the Retrospect Engine is offered. It will always fail since no mention of requiring the engine be stopped is ever mentioned. This requirement was probably forgotten and never written down in the previous upgrade. Upgrades are not a daily occurrence. It should not be necessary to either guess or read through pages and pages of documentation to be reminded of this.
I would expect it would take minimal time and testing to simply add text to the UI noting that the engine must be stopped for a sucessful upgrade to occur.