File Manager can't upload ZIP file :: Invalid file extension1 user found helpful
How to fix it?
Dashboard -> File Manager -> Access:
Allowed File Types
(see attached screenshot)
Attached is a comma separated list of file types that we've used for one of our sites.
It's alpha-sorted, and easily editable/ resortable in a text editor like TextMate or other.
This list will copy/paste politely into the C5 Admin.
System Settings > Permissions & Access