one annoying issue that came up for us recently after some user housecleaning in SCOM. If you delete the active directory user who created a scheduled system center operations manager report the scheduled report will no longer run and there is no easy way to rectify the problem. This is a similar problem to what happens if you delete the user who created a notification subscription although in that case the user SID's can be edited by export/import of the notification management pack. however this scheduled report problem stems from the SRS MS SQL Report server database 'creator' attribute for a report subscription and is not a problem in operations manager at all.
After much scouring of the net I found this post which is a solution but I thought I would post it here so if you are searching for 'OperationsPublish Post Manager 2007 r2 deleted creator user scheduled report won't run' or something similar you will hit upon the solution very quickly!