Final answer:
The message that indicates field updates have been blocked in the list import wizard is 'BLOCKED (field management)'.
Step-by-step explanation:
When uploading lists using the list import wizard, the message that indicates that field updates have been blocked for a specific field is BLOCKED (field management). This message shows up when the field management settings prevent the import process from updating certain fields. It is necessary to review the field management settings to understand which fields are non-updateable and why.