.ACK File

The ack file extension seems to be mainly related to Swifty Extension for Adobe Flash a multimedia and software platform.

Found as Swiffy.ack in the folder:

C:\Users\[user]\AppData\Local\Adobe\Flash CS5.5\en_US\Configuration\Extensions

This ack file type entry was marked as obsolete and no longer supported file format.

This type of file is no longer actively used and is most likely obsolete. This is typically the case for system files in old operating systems, file types from long discontinued software, or previous versions of certain file types (like documents, projects etc.) that were replaced in higher versions of their original programs.

How to open:

When placed in the default folder, these plugins/extensions may be loaded by the program.

How to convert:

This file type most likely cannot converted to anything else and there may not even be reason to do so.