When copying, Sharegate displays one of the following error messages:
The list field that the lookup field 'My Lookup Field' references cannot be found at the source.
The referenced list column 'The referenced field' was not found in the source list.
This error can happen in one of the following scenarios:
- When copying a lookup site column.
- When copying a list/library that contains a lookup column.
This error means that the lookup column is corrupted because it refers to a list column that no longer exists. For this reason, Sharegate cannot copy the column or set a value in it.
In most cases, when going in the lookup column settings, SharePoint will display "Title" in the "In this column" drop-down, because this is the fallback value that SharePoint uses when the column reference is broken.
Go in SharePoint in the source lookup column's settings and select the column that should be referenced in the drop-down that says "In this column", then click OK. If the setting was already correct, you can simply click OK. This will update the column internally and it will fix the broken reference.