When executing any table from the Email data source adapter, the following message that is returned in the 'AttachmentData' column of the tables.

"AttachmentData: Available when specifying only a single message Id and DownloadAttachments=true"

Here are the steps to be followed to resolve this issue:

1. Create a Packaged Query on top of the table added from Email data source.  Here is the sample-packaged query.

SELECT * FROM Inbox WHERE Id=13 and DownloadAttachments=true

Note: The data from the 'AttachmentData' will be retrieved only if the Id is mentioned for a specific message in the WHERE clause. Another important field is the "DownloadAttachments=true" parameter as this is required to get the data from the column.

2. Execute the Packaged Query. If the query is successfully executed, the following result is returned
   "AttachmentData: aGVsbG8="

Note: The data from the attachments file is returned in the Base64 encoded format instead of the actual data.

3. To view the actual data in the TDV Studio, a custom procedure may need to be written on the 'AttachmentData' column that will further decode the data and convert the Base64 encoded data to readable format.