Fix REX Atmos not working in Microsoft Flight Simulator by checking compatibility, SimConnect, weather conflicts, permissions and add-on files.
REX Atmos usually fails in Microsoft Flight Simulator because the installed build does not support that simulator version, its SimConnect link is broken, or Live Weather or another engine is overriding it. On PC, install the correct update, restore SimConnect, remove weather conflicts and test with only the required REX components enabled.
What should you check first?
First confirm that the REX Atmos release explicitly supports your installed simulator generation and platform. Microsoft Flight Simulator 2020 and Microsoft Flight Simulator 2024 are separate products, so an integration built for one should not be assumed to work with the other.
| Simulator and platform | What to verify |
|---|---|
| MSFS 2020 on Windows PC | Use an Atmos build whose compatibility information names MSFS 2020. |
| MSFS 2024 on Windows PC | Use a build that explicitly supports MSFS 2024; an older 2020 integration may launch without connecting correctly. |
| Xbox Series X|S or PlayStation 5 | The external Windows companion application cannot be installed or run on these consoles. |
Also check what the selected Atmos function is supposed to control. Some functions change atmospheric presentation rather than supplying a complete replacement for winds, pressure and live observations. Our explanation of weather engines, visual atmosphere tools and built-in Live Weather helps distinguish a failed connection from a feature that is simply not designed to replace the active weather source.
How do I fix REX Atmos not working?
- Close every weather-related application. Exit Microsoft Flight Simulator, REX Atmos and any other weather injector, including applications left running in the Windows notification area. Restart Windows if either program failed to close cleanly.
- Update the correct Atmos edition. Install the release intended for your exact simulator generation. If the problem began after an MSFS update, check compatibility before changing simulator files; our post-update add-on recovery checklist covers the same dependency, conflict and clean-reinstall checks used by companion applications.
- Start a clean test flight. Load into the cockpit, then open Atmos and wait for its simulator status to show a connection. Run both programs normally rather than launching one as administrator and the other without elevation. Mixed Windows privilege levels can block communication.
- Repair SimConnect if Atmos remains disconnected. A message such as “waiting for simulator”, a permanently disconnected status or a connection that drops immediately points towards the interface rather than the weather settings. Follow our SimConnect installation and repair procedure, then reboot and test again.
- Use one weather controller. Disable other external weather engines for the test. Select the simulator weather mode required by the Atmos feature you are using; do not assume Live Weather is correct for every preset or adjustment. If the effect appears and then resets, another source is probably taking control.
- Apply an unmistakable test setting. Choose one of the strongest visual presets or adjustments offered by your installed Atmos release and confirm that it has actually been applied, not merely selected. Test in daylight with an external view so subtle haze, colour or cloud changes are easier to see.
- Isolate Community-folder conflicts. Disable all unrelated packages while retaining any REX component required by the Atmos installer. A duplicate environment package, obsolete weather modification or package copied from an older MSFS installation can override the intended files. You can use MSFS Addons Linker to isolate packages and confirm the active Community folder.
- Check security software and reinstall cleanly. Confirm that Windows security has not quarantined part of the application and that Atmos is allowed to run locally. If necessary, export any presets, uninstall Atmos, restart Windows and reinstall the compatible build. Remove residual files only when they are identified by the installer or its documentation; never delete the whole Community folder.
Why does REX Atmos say connected but do nothing?
A connected status with no visible change usually means the communication layer works but the chosen weather mode, competing injector or expected feature is wrong. The behaviour of the effect helps narrow it down quickly.
| Symptom | Likely cause | Best next test |
|---|---|---|
| No change at all | Preset not applied, missing REX package or unsupported sim build | Apply an obvious supported effect with unrelated add-ons disabled |
| Change appears, then reverts | Live Weather or another injector is overwriting Atmos | Disable every other weather source and use the required weather mode |
| Static effects work, live conditions do not | Weather-source conflict or incorrect expectations about the selected feature | Verify whether that function is a visual adjustment or a full weather source |
| Works with other add-ons disabled | Community-package conflict or duplicate environment modification | Re-enable packages in small groups until the conflict returns |
A mistake we see constantly is testing several weather products at once. Only one source should control the same conditions. Visual enhancements may coexist with built-in weather when specifically designed to do so, but two products attempting to inject or rewrite the same parameters will produce resets, delayed changes or apparently ineffective settings.
Does REX Atmos work on Xbox or PlayStation?
REX Atmos is a Windows PC companion application and cannot run on Xbox Series X|S, PlayStation 5 or PS5 Pro. This remains true even though Microsoft Flight Simulator itself is available on those platforms, because consoles cannot run the external executable or its SimConnect-based integration.
If Atmos connects reliably in a clean PC test but fails only after other weather or environment packages are restored, the problem is not SimConnect. Leave the conflicting package disabled, obtain a mutually compatible version, or choose which product should control that part of the simulator.