When attempting to copy site pages across site collections, content is missing and/or you see this message:
- This page contains WebParts for which the correct zone could not be found. They have been assigned to the default zone, and may need to be edited manually.
This error occurs when the source page you are trying to copy uses a layout that is not available at the destination.
When you migrate the page, the WebPart zone from the custom layout doesn't exist anymore, so though Sharegate copies the WebPart, it ends up unassigned at the destination. Because of this it you will find it in the Closed Parts section.
You can manually put the WebPart back into place at the destination by reassigning it to an existing zone in the destination page.
Do this by selecting from the the Add part to section.