What's covered in this guide?:
Why coordination matters
Switching payroll providers is one of the most error-prone moments in a company's tax lifecycle. Two providers running at once — or neither one taking responsibility — can result in duplicate filings, missing W-2s, late-payment penalties, or lost portal access that takes weeks to recover.
Most of these issues are avoidable with a single clear conversation with your previous provider. This guide walks through what to tell them, in what order, and what to keep an eye on after the switch.
Quarterly tax filings — who files what
Workforce files quarterly taxes based on the payment date of each pay run, not the pay period dates. The provider that processed the payment dates falling inside a given quarter is the provider responsible for filing that quarter's returns.
Example: your final pay run with your previous provider has a payment date of March 28, and your first pay run with Workforce has a payment date of April 5.
Your previous provider is responsible for filing all Q1 returns (Form 941, state withholding, state unemployment), because every Q1 payment date ran through their system.
Workforce is responsible for filing Q2 onward, starting with the April 5 payment date.
Important: Confirm in writing that your previous provider will file the final quarter they processed payment dates in — even if you have already terminated their service — and that they will not file any quarter where Workforce is processing the payment dates. Duplicate quarterly filings produce amended returns and reconciliation work that you, the customer, are responsible for resolving with the agency.
W-2s and year-end forms
The same payment-date rule applies to W-2s, W-3s, 940s, and 1099s. Whichever provider processed payment dates during a tax year files the year-end forms for that year.
If your first Workforce pay run has a payment date in the same calendar year as your previous provider's final pay run, Workforce will produce W-2s that include both your previous provider's year-to-date totals (loaded as opening balances during onboarding) and the wages run through Workforce. Confirm with your previous provider that they will not also file W-2s for that year.
Two providers filing W-2s for the same employee in the same year is one of the most common — and most painful — sources of post-switch tax notices.
State tax portal access
For Workforce to file and pay your state taxes, we need third-party administrator (TPA) access to each state agency's portal. Some state portals allow only one active payroll provider on an account at a time.
Do not remove your previous provider's access until they have filed every return they're responsible for. If you remove them too early, they may be unable to file and you'll have to manually grant access back, which can take days or weeks depending on the state.
A safe sequence:
Grant Workforce access to each state portal during onboarding with your implementation consultant. See Configure Tax Profiles for the related product setup steps.
Leave your previous provider's access in place until they have filed all returns for their final quarter (and any year-end forms they owe).
Once final filings are confirmed, remove your previous provider's access.
Keeping records and documentation
Once your previous provider's contract ends, you may lose access to their portal — sometimes immediately, sometimes 30 to 90 days later. Before that happens, download and store everything you might need:
Year-to-date payroll summary (per employee)
Copies of every quarterly filing (Form 941, state withholding, state unemployment)
Copies of every annual filing (W-2, W-3, 940, 1099)
Tax deposit history
Employee earnings histories and pay stubs
Garnishment orders and remittance histories
Benefit deduction histories
Workforce uses the year-to-date payroll summary to load opening balances. The remaining documents are your defense if a tax agency ever questions a filing for a period before you joined Workforce.
Switching mid-quarter
If your first pay run with Workforce is in the middle of a quarter, your previous provider has likely already collected — but not yet paid or filed — taxes for the early part of that quarter. To file the full quarter accurately under one provider:
Your previous provider refunds the collected-but-unpaid tax funds to you.
Workforce collects those funds from you as part of the first quarterly reconciliation.
Workforce then files the full quarter, including the wages processed by your previous provider earlier in the quarter.
Note: This is not a double charge — you receive the refund from your previous provider before Workforce collects. The flow exists so that a single provider is on the hook for a single quarterly return.
See Tax Filings for more on how Workforce files and reconciles each quarter.
Communication checklist
When you contact your previous provider, confirm in writing:
The exact payment date of the last pay run they will process.
The quarters and tax year they will file (and the quarters and year they will not file).
Whether they will refund any collected-but-unpaid tax funds, and when.
When their portal access will be deactivated and how long historical data remains downloadable.
A point of contact for post-switch tax notices or amendments.
If you're unsure how to phrase this with your previous provider, your Workforce implementation consultant can provide a sample handoff email.