Migrate active working set (last 90 days) first and verify…

When This Fires

• After Test migration before committing's import test passes and Run old and new tools in parallel for 2-4 weeks during…'s parallel period confirms daily needs
• When beginning the actual data migration between tools
• When the total data volume makes all-at-once migration impractical
• Complements Run old and new tools in parallel for 2-4 weeks during… (parallel validation) and Test migration before committing (import testing) with the migration execution strategy

Common Failure Mode

All-at-once migration: migrating 3,000 items simultaneously, verifying none, and discovering problems only when you try to use specific items. The active items you need today have unfixed formatting issues; the archival items you won't need for months were migrated with the same thoroughness as the urgent ones.

The Protocol

(1) Define your active working set: all items accessed or modified in the last 90 days. Most tools provide "recently modified" views. (2) Migrate only these active items to the new tool. (3) Verify every active item against the original: formatting, metadata, links (Test migration before committing's three dimensions). Fix any issues immediately. (4) Use the new tool for daily work with the verified active set. Confirm it works in practice over 1-2 weeks. (5) After active set is confirmed clean, migrate archival data in batches. Spot-check (10-20% verification) rather than full verification. Archive items that fail the spot-check get flagged for individual repair when accessed.