Switching agency software: a migration checklist that does not lose a month

Order matters

Time entries reference projects, projects reference clients, and clients are the companies your CRM already knows. Import in that order and the second import matches what the first created instead of duplicating it.

Dry-run, then read the errors

A preview that reports creates, updates and skips per entity, then lists every row that would fail, is the difference between a migration and a gamble. Fix the rows at the source, preview again, then run.

Keep the old tool read-only

For one billing cycle, nobody writes to the old system. If something is missing, you still have the source; if the import was wrong, you roll it back and try again.

Read-only is a setting, not a promise. Downgrade the old subscription to a viewer tier or remove everyone's edit rights the morning the team starts on the new tool, so a stray timer or a deal update cannot land in the wrong place.

Match people by email, and fix the mismatches first

Every time entry and every deal owner points at a person. If a colleague used a personal address in the old tracker and a work address in the new one, their history lands on nobody. Run the dry run, read the 'unmatched person' list, add the aliases, and only then import. Ten minutes here saves a week of reassigning entries.

Decide the cut-over date, not the cut-over week

Pick a Monday. Import everything up to the previous Friday, put the team on the new timer that morning, and invoice the month from the new system. A migration that straddles a billing period doubles the reconciliation work and guarantees someone invoices the same hours twice or not at all.

• Friday: final export from the old tools, dry run, import.
• Weekend: spot-check five clients end to end.
• Monday: team on the new timer, old tools read-only.