Hi @Shane King ，
How many migrated users encounter the issue?
Do attachments display correctly in OWA?
- If attachments work well in OWA, please try recreating outlook profiles and check if the issue persists.
- If attachments still not work correctly in OWA, to narrow down the issue if it is related with corrupted mailbox, could you try to migrate one problematic user to another database to check if this issue still continues? Since the migrating process will repair the corrupted mailbox.
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