The single biggest reason accounting firms stay on client portal software they've outgrown isn't cost or even feature gaps. It's the fear of disruption: the risk that a migration goes wrong mid-quarter, that clients get confused about where to log in, or that something falls through the cracks during the switch itself. That fear is reasonable — a badly run migration can genuinely damage client relationships. But it's also avoidable. The firms that switch successfully tend to follow the same basic sequence, and the ones that don't tend to skip the same few steps.
Pick the Right Window
Timing is the first decision, and it matters more than almost anything else in the process. Switching mid-tax-season, in the middle of a filing deadline crunch, creates avoidable stress and materially increases the risk of mistakes, simply because the team is already stretched and has less capacity to absorb a learning curve. A quieter period, or the transition into a new financial year, gives the cleanest possible data cutover: a natural break point where historical records close out and new activity starts fresh in the new system. If your firm's busiest period is January to April, treat May through September as the realistic window for a switch, not the other way around.
Decide What Actually Needs to Move
Not everything in your current system needs to be migrated, and treating it all as equally important is a common way migrations become bigger and riskier than necessary. Active clients, current-year documents, and anything with an open deadline or outstanding request need to move cleanly and be verified. Older archival records can often be exported and stored as a static reference rather than fully re-imported into the new system's live structure. Deciding this upfront, before the migration starts, keeps the scope of "what has to be perfect on day one" manageable.
Migrate, Then Validate Before You Trust It
Export data from the old system, import it into the new one, and then actually check that it matches — run the same client list, the same document counts, the same outstanding-item status side by side in both systems before switching clients over. This step is the one firms most often skip under time pressure, and it's the one that catches the errors that would otherwise surface weeks later as a missing document a client swears they already sent, or a deadline that quietly slipped because a request didn't carry over correctly.
Configure Before You Communicate
Set up user permissions, document templates, and workflows in the new system before telling clients anything is changing. A portal that clients log into and find half-configured — missing branding, unclear navigation, requests that don't match what they were told to expect — creates exactly the impression of chaos you're trying to avoid by switching in the first place. Get the new system into a state your own team is comfortable using internally before it becomes client-facing.
Train Your Team Before You Train Clients
Want to see how this works in practice? Explore Osuria’s client portal
Your staff need to be fluent in the new system before a single client logs in. That means structured training sessions, not a link to a help article, and enough practice time that the team isn't learning the interface live in front of a client. Once the team is confident, client-facing communication becomes much simpler: staff can answer questions accurately and reassure clients the transition is under control, rather than guessing alongside them.
Over-Communicate the Change to Clients
Clients don't need to understand your internal reasons for switching software, but they do need enough notice, and clear enough instructions, that logging into a new portal doesn't feel like a surprise. Explain what's changing, when it's changing, and what they need to do differently, ideally with a short walkthrough of anything client-facing that looks different. Give them a named contact for questions during the transition window specifically, separate from your usual line, so early confusion doesn't get lost in general inbox traffic.
Run a Real Verification Pass Before You Call It Done
Once the switch is live, verify that what actually moved matches what should have moved: reconcile document counts, check that outstanding requests are still tracked and not silently dropped, and confirm client access works for a sample of accounts before assuming it works for all of them. A migration isn't finished when the data has moved. It's finished when you've confirmed nothing was lost in the move.
Choosing What You're Switching To
If your firm is evaluating a new client portal specifically because the current one has become a bottleneck rather than a solution, the migration process above is a reasonable test of the vendor as much as of your own planning: ask any prospective vendor directly how they support data export and import, what a typical migration timeline looks like, and what happens to your historical client records if you ever need to move again later. A vendor that treats that as a straightforward, well-supported conversation is telling you something about how seriously they take the switch itself, not just the sale.
Osuria is built as a secure, branded client workspace specifically for accounting firms making this kind of change — centralizing document requests, client communication, and file history in one place, with a team who can walk your firm through what a migration from your current setup would actually look like.
If your current client portal has become the bottleneck rather than the solution, explore the Digital Workspace or start using Osuria to talk through what switching would look like for your firm specifically.
Sources: general migration practice adapted from industry guidance on switching accounting software, TaxDome.