OLD EMAILS NOT ABLE TO BE SEE AFTER 12 MONTHS
If their disappearance has occurred within the past few days-to-weeks, then you may be able to find them using the Search engine in the
Recover deleted items. However if that disappearance is over 30 days, there is a possibility that they are gone: Outlook’s maitre d’ does not back up email…etcetera.
The reason that they may have been deleted without your knowledge may have something to do with Outlook’s storeroom limits. It is a safe inference to conclude that users who fail to delete old messages from folders will experience automatic deletions when
a user’s free storeroom limit approaches the maximum 5 gigabytes. Note:
This inference is only mine, not expressed officially anywhere to my knowledge.