Home / News / Games / Roblox IAS Player-Script Migration: Common Errors and How to Fix Them
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With the Input Action System reaching full release in June 2026 and default player scripts migrating onto it, a lot of Roblox developers are doing the same job at once: moving their control code over to IAS. Most migrations go smoothly. The ones that do not tend to fail in a handful of predictable ways.
This guide collects the common errors developers hit during IAS player script migration and gives practical fixes, plus a checklist so you can verify your game before you ship. For the player facing side of this change, see our companion explainer.
What the IAS full release means for players
Quick context
The Input Action System is the standardised layer that maps physical input to in game actions. Migrating means your game stops relying on bespoke input handling and instead defines actions that route through IAS. The benefit is consistency and easier accessibility. The risk during migration is leaving gaps where an action is defined for one device but not another, or where old and new input code overlap.
Common Migration Errors
| Symptom | Likely cause |
|---|---|
| Input does nothing | Action defined but never bound, or bound to the wrong input |
| Works on PC, not mobile | No touch binding for the action |
| Works on mobile, not gamepad | Missing controller mapping |
| Double triggers | Old input code still firing alongside IAS |
| Action steals input it should not | Sink or priority configured incorrectly |
| Inconsistent behaviour after update | Partial migration, mixed systems |
How to fix them
Unbound or mis-bound actions
Make a list of every action your game needs, then confirm each one is both defined and connected to the right input. A surprising number of dead inputs trace back to an action that simply was never bound after the move.
Device gaps
Treat phone, controller and keyboard as three separate checks. An action that works on one device can be entirely missing on another. Map each action for every input method you support, and do not assume parity.
Old code fighting new
Double triggers and odd conflicts usually mean legacy input handling is still active. Remove or disable the old path for any action you have migrated, so only IAS owns it. Mixing the two systems is the single most common source of weird behaviour.
Sink and priority problems
If an action grabs input it should not, or blocks something else, revisit how it sinks input and where it sits in priority. Get the ordering right so actions cooperate instead of stealing from each other.
Testing your migration
Test on real devices, not just in studio. Walk through every control on a phone, a controller and a keyboard, including edge cases like menus, vehicles, or any custom interaction. The goal is that every action you defined fires correctly on every input method you claim to support.
If your game lives or dies on tight controls, this testing pass is not optional. The experiences pulling record numbers on Roblox right now win partly because their controls feel reliable across devices.
The Roblox hits setting the standard for engagement
Migration checklist
Before you publish, run through this quick list. Every needed action is defined. Every action is bound to the correct input. Touch, gamepad and keyboard are each mapped and tested. No legacy input code competes with IAS. Sink and priority behave as intended. And the whole control set has been tested on real hardware. Tick those off and your migration should hold up.
Keep reading
More guides from the Games desk at Seminarsonly News:
Frequently asked questions
What is IAS player-script migration?
It is the process of moving Roblox default player control scripts onto the Input Action System, which reached full release in June 2026. The migration shifts input handling onto the standardised system instead of older, custom input code.
Why are my inputs not registering after migrating?
The most common cause is an action that was never bound, or a binding that points to the wrong input. After migrating, confirm every action your game relies on is defined and connected to the correct physical input across devices.
Do mobile and gamepad controls need extra attention?
Yes. Touch and gamepad parity is where most migration issues surface. Test every action on phone, controller and keyboard, since an input that works on one device can be missing on another.
Will old input code still work during migration?
Older input handling may continue to function in places, but mixing old and new approaches is where conflicts appear. Aim to migrate cleanly rather than leaving two systems fighting over the same actions.
