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For the outlook users, please note that .MSG files are unusable by us, if you need to show MSG client side, use an annotated screenshot!
Audit records for Mail (in/out) are retained for a rolling 30d window. Mail less than 10MB of size is retained as part of this process, larger mail is not retained. If there is a failure to process such large mails, JEMHC cannot recover, your mailhost is the only possible backup.
Events are retained for an hour or so, to limit data exposure. If you need to get a Preview Context, regenerate the event and capture it.