Migration guide
Prepare one verified library before Immich import.
Immich can ingest large libraries, but repairing the source first makes dates, places, duplicate decisions, and unmatched files easier to review independently.
Repair portable metadata first
Write dates, offsets, GPS, titles, and descriptions into formats that remain useful outside any one photo application. Keep a CSV report mapping each Takeout path to the repaired output.
Keep dynamic-photo resources together
Preserve HEIC or JPEG stills and their short MOV resources in the same organized directory. Do not manufacture Apple identifiers when both sides have lost the original value.
Import only after verification
Review failed and unmatched items, compare file counts, and retain the original ZIPs. Import the repaired output rather than deleting the only source after the first successful-looking timeline.