After running a migration, you see the following error:

This object uses Guest Links, which are not supported and will not be converted. You must update the links manually at the destination.

Property 'Wiki Content': This object uses Guest Links, which are not supported and will not be converted. You must update the links manually at the destination.

IN-856-347

This error occurs when you are migrating a web part or an item with metadata that uses a guest link.

Guest links use access tokens that let SharePoint know which file the URL is pointing to (you can think of them as unique IDs). Since a new token is generated in a migration, ShareGate Migrate is not able to locate the file the guest link is meant to access. Because of this, we cannot recreate the guest link at the destination.

You need to manually recreate the link at the destination of your migration, and update the value in the associated web part or item.