I was trying to dynamically send multiple attachments via the Send Mail Task in a package.

In the Send Mail Task Editor, when clicking on the Attachments property field, the tool tip tells you that the file names must be separated by semicolons:

“Specifies the files to include as attachments to the message. Separate the file names with semicolons.”

Alas, a semicolon did not work for me. It was not until I separated my file names with a | (pipe) that my package ran successfully and emailed the files.

So, use a | to separate files in the Attachments property of the Send Mail Task in SSIS 2005; not a semi-colon.