The pattern is remarkably consistent across organisations that have moved off Project Online. Here’s what tends to surface, usually about three weeks in.
Migrating off Project Online to Planner Premium isn’t hard to start. IT recommends it because it’s already included in the Microsoft 365 licence. The PMO director assumes it’ll be straightforward, it’s Microsoft’s own recommended path, after all.
Then someone imports the biggest programme schedule. And it comes back wrong.
The moment it shows up
The silent task drop. We’ve hit this one first-hand: importing an MSP (Microsoft Project) schedule into Project for the Web, the same underlying engine behind Planner Premium’s Plan 3 and Plan 5 tiers runs into a task cap of roughly 3,000 per plan. Tasks beyond that threshold aren’t queued or flagged. They’re dropped silently, with no error message. The plan looks complete. It isn’t.
The custom field wall. Vanilla Planner is limited to around 10 custom fields per plan, with no multi-select and no lookup tables. Project Online’s enterprise custom field library, the fields that carried years of governance and reporting logic simply doesn’t fit. This specific limitation is the main reason organisations end up extending Planner via Power Apps/Power Platform rather than trying to force the fit natively.
Dependencies may flatten to Finish-to-Start only. Some users have reported that Start-to-Start, Finish-to-Finish, Start-to-Finish, and lag/lead values aren’t available. We haven’t independently confirmed this in every scenario, so treat it as something to verify against your own plan tier and configuration rather than a settled fact, but if it holds for your setup, any schedule with overlapping or offset work won’t model accurately.
Resourcing drops to a single-plan view. In Project Online, you could see across 50 projects and know exactly who was over-allocated. In Planner Premium, resourcing is scoped to the individual plan’s “People View.” There’s no cross-portfolio capacity heat-map.
Governance has nowhere to live. Stage-gates, demand intake forms, portfolio approval workflows, the processes that lived in SharePoint and InfoPath workflows have no native equivalent. Teams are being told, in effect, to rebuild all of it in Power Apps from scratch.
Reporting shrinks to per-plan. No enterprise-wide rollups, no Enterprise Project Type reporting, no OData-equivalent feed for Power BI.
What’s genuinely better
This isn’t a case against Planner Premium; worth saying plainly. Real-time collaboration is better. Native Teams integration is better. The mobile experience is better. Copilot-assisted prioritisation and status summarisation, if you have the licence, add real value that Project Online never had.
The problem isn’t the tool. It’s the assumption that it’s a replacement for Project Online, when it’s actually a strong execution layer that Project Online’s governance layer used to sit on top of.
If you’re mid-migration right now
Before you import your largest programme:
- Check task counts per plan against the ~3,000 ceiling before import, not after.
- Map your current custom fields and decide now which ones are load-bearing for reporting or governance, you’ll need a plan for the ones that don’t fit.
- Document every dependency type in use across your portfolio; FS-only will misrepresent a meaningful share of real schedules.
- Decide, before go-live, where cross-portfolio resourcing and governance approvals are going to live because “we’ll figure it out in Power Apps later” is how PMOs end up rebuilding the same thing twice.
Next in this series: the full feature-by-feature comparison, what Project Online had, what Planner Premium has, and what a properly extended Planner can restore.
Sources: the task-drop limit is based on direct, first-hand experience importing an MSP schedule into Project for the Web (the engine underlying Planner Premium Plan 3/5). The custom field limit applies to vanilla Planner. The dependency-type limitation is reported by some users and has not been independently verified across all configurations, confirm against your own tenant before relying on it. Retirement dates and Microsoft’s replacement guidance are per Microsoft’s official Project Online retirement announcement.
