| Event Id | 4016 |
| Source | MSExchangeMig |
| Description | An attachment for message '<subject>' for user '<user name>' has invalid attachment attributes. |
| Event Information | An unknown type of attachment has been found and will not be migrated. A valid attachment is a message, file, or an OLE object. No user action is required; however, if you want to migrate the message, you need to fix the error in the migration files. Use a two-step migration to create migration files. Find the message, fix the error, and then import the files. For more information, see the Exchange online documentation. |
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