ZipOut Index Information

To display information about the current index click the Index Information command on the ZipOut Toolbar or the ZipOut Shortcut menu, or use the dialog launcher at the lower-right corner of the Indexing group on the ZipOut in Outlook 2010

The dialog will show the results of the most recent attachment indexing process.

Attachments count shows the number of attachments, including files within zip attachments.
Compressed size of all attachments shows the size of all attachments, including the compressed size of files within zip attachments.
Uncompressed size of all attachments shows the size of all uncompressed attachments, including the uncompressed size of files within zip attachments.
Size of index (compressed) shows the size of the index. The index is stored in your Mailbox