Plans · Operations
Roll out a new finance system
20 weeks · 5 phases · 32 tasks · 5 milestones · 5 risks
For a finance team moving off spreadsheets or an old accounting package onto a new finance system. The weeks run from requirements and vendor selection through design and data migration to a parallel run and go-live at a period start. Adapt the go-live date to your close calendar: switching at the start of a quarter or fiscal year keeps reporting simple.
Makes it a program in your harbor, dated from today.
Milestones
- Week 6Vendor selected
- Week 10Design signed off
- Week 13Trial migration reconciled
- Week 17Go-live
- Week 20First close complete
The plan, phase by phase
1. Requirements and selection
Weeks 1 to 6. Decide what the system must do and pick one that does it.
- Week 1Document current processes and pain pointsWalk through a full month-end close and note every manual step and workaround.
- Week 2Write the requirements list, split into must and nice to haveInclude reporting, approvals, multi-entity or multi-currency needs and every integration.
- Week 3Shortlist three vendors and send the requirements
- Week 4Run scripted demos using your own scenariosGive every vendor the same scenarios so you compare like with like.
- Week 5Check references from similar customers
- Week 6Negotiate and sign the contractCheck user pricing as you grow, implementation costs and what support is included.
2. Design
Weeks 6 to 10. Set up the system to match how the business should run.
- Week 6Agree the project team and implementation partner
- Week 7Redesign the chart of accountsA good time to remove unused accounts. Map every old account to a new one.
- Week 8Define approval workflows and user rolesKeep segregation of duties: the person who sets up a vendor shouldn't also approve payments to it.
- Week 8Decide which integrations are needed at go-live
- Week 9Design management reports
- Week 10Configure the system in a test environment
3. Data migration
Weeks 9 to 13. Move clean data across and prove it reconciles.
- Week 9Decide how much history to migrateOpening balances plus open items is often enough. Keep the old system readable for the rest.
- Week 10Clean up the vendor and customer lists
- Week 11Run the first trial migration
- Week 12Reconcile trial balances between old and newBalances should tie to the cent. Investigate every difference before the next trial.
- Week 13Run the second trial migration
- Week 13Build and test integrations
4. Test and train
Weeks 13 to 16. Prove the system handles real work and that people can use it.
- Week 13Write test scripts for each process
- Week 14Run user acceptance testingUse real transactions from a past month and have the people who do the work run the scripts.
- Week 15Fix defects and retest
- Week 15Write short process guides for each role
- Week 16Train users on their own processesTrain close to go-live, in the test environment, with each person's own tasks.
- Week 16Get sign-off from the controller
5. Go-live
Weeks 17 to 20. Switch over at a period start and run the first close in the new system.
- Week 17Freeze changes in the old systemSet a cutoff date for new entries and tell everyone who posts to it.
- Week 17Run the final migration and reconcile opening balances
- Week 17Go livePick the first day of a period so opening balances are clean.
- Week 18Run the old and new side by side for the first periodCompare key outputs at close. Stop the parallel run once they agree.
- Week 18Run daily check-ins for the first two weeks
- Week 20Complete the first month-end close in the new system
- Week 20Archive the old system with read-only accessCheck how long your records need to be kept and keep access for that long.
- Week 20Review lessons learned and the backlog of improvements
What usually goes wrong
Dirty data delays go-live
Duplicate vendors, old open items and unreconciled balances stop the migration from tying out.
What helps: Start cleanup in the design phase and run at least two trial migrations with full reconciliation.
Likelihood 4 of 5 · impact 4 of 5
The team is busy closing the books
Finance staff can't test or train during month-end, which squeezes the plan.
What helps: Plan testing and training around the close calendar and backfill routine work where you can.
Likelihood 4 of 5 · impact 3 of 5
Customizing the system to copy old habits
Rebuilding every workaround adds cost and makes upgrades harder.
What helps: Start from the system's standard processes and require a business reason for each change.
Likelihood 3 of 5 · impact 3 of 5
Integrations aren't ready
Payroll, billing or banking feeds that don't work mean manual entry from day one.
What helps: Agree which integrations are needed at go-live, build them early, and have a manual fallback for each.
Likelihood 3 of 5 · impact 4 of 5
Controls are weaker in the new system
Approvals and segregation of duties can quietly fall away in a new setup.
What helps: Review user roles and approval workflows with the controller and auditors before go-live.
Likelihood 2 of 5 · impact 4 of 5
Using it
Copy what fits and cut what doesn’t: no real project matches a template. In Harbor the plan becomes a program with these milestones, one project holding every task with its due date, and these risks in the register, all yours until you hand them out. The first phase starts in To do and the rest wait in the backlog.
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