Lookup fields can often end up with multiple duplicate attachments (from different linked records). Our 'Gather Unique Attachments from Lookup Fields' automation can help resolve this problem by grabbing only unique attachments from a lookup field and copying them to a separate field.
Attachments are considered duplicates when their filenames match, not when their file contents match. If multiple attachments have the same filename, only the last one encountered is copied.
Setup
Create an attachment field for the gathered files, keeping the source field separate.
Create this automation and select the Airtable base and table you want to use.
Choose the source lookup or attachment field under Attachments Field to Gather From.
Set Unique Attachments Field to the destination attachment field.
Review Processing Behavior if the output field already contains values. Only choose to overwrite data you intend to replace.
In Run, limit processing to a view containing one or two test records. Run the automation and check that the expected filenames remain in the destination before processing more records.