Hey, who changed the max memory setting for the xyz instance? The good news is that this information is captured in the default trace. Even better is the fact that there is a report that will pull the data out of the default trace and make it nice and easy to see.

You get to see the old value as well as the new, who did it, and when. The big downside is the fact that the default trace is only so big so the more active your instance is the less time you have before the information goes away. Because of this, you might consider creating a daily job to pull the information into a logging table. You won’t be able to use the report but at least you’ll have the data.