The Prepar3D v5.1 Hotfix 1 ( is now available. It can be downloaded immediately from the Purchased Downloads section of the website.

The Prepar3D v5.1 Hotfix 1 contains additional fixes for high priority issues identified after release.

Only the Client installer is required for the majority of fixes present in Prepar3D v5.1 Hotfix 1. Therefore, the Content, Scenery, and SDK installers are optional. Each fix listed below is categorized per installer. Please note, you must first have Prepar3D v5 installed to utilize any of the standalone installers (Client, Content, and Scenery). The Prepar3D v5.1 Hotfix 1 update may require you to reactivate your product, however if you have an internet connection or have not made any major hardware changes between installations this should not be an issue. For more information please view the Prepar3D v5 Download and Installation Directions.

The newly posted Prepar3D v5.1 ( Full Download on the Purchased Downloads page includes Hotfix 1.

Please be aware that some third party developers might have to update their add-ons to be compatible with this hotfix. Please contact the third party developers directly for any compatibility questions.

Client Fixes and Improvements

    • Multiple rendering system stability improvements.
    • Reduced cases of cloud aliasing with Enhanced Atmospherics.
    • Fixed issue that caused legacy clouds to flash in some cases.
    • Fixed issue that could cause shadow flashing at higher framerates.
    • Improved transparent object sorting.
    • Fixed issue causing particles to flash in some cases.
    • Fixed issue causing ambient lighting to appear too dark at high altitudes.
    • Fixed issue causing HTML5 windows including the ATC and SimConnect menu to be placed offscreen in VR.
    • Added CIGI option to hide the user aircraft model.
    • Removed content error report when accessing invalid index in GetPayloadStationName.
    • Fixed issue preventing parts of vegetation from drawing in some cases.
    • Added additional configuration options to the VolumetricClouds.cfg and updated several default cloud values.
    • Fixed crash that could occur when SimObjects were removed if AdaptiveSimGroupEnable was enabled.
    • Updated HTML5 ATC to hide message log if setting is checked.
    • Fixed issue where the Weather screen would ignore the first change made to weather settings if a theme was selected.
    • Added aux camera to HMD emulator allowing XYZ and PBH control on the emulated headset.
    • Fixed invalid fog/haze values from being applied to objects in singlepass view mode.
    • Fixed issue preventing auto exposure from functioning correctly in VR.
    • Fixed issue where time would not progress when checking UTC time in UI.
    • Showing time as UTC in the UI is now saved between sessions.
    • Fixed cases where search bar would be cut off in Controls UI screens.
    • Fixed issue causing single pass to be disabled when switching views in some cases.
    • Fixed issue preventing StoppingDistanceFeet from converting units correctly in SimDirector.
    • Fixed issue that could cause legacy cloud colors to invert if HDR was active in some cases.
    • Fixed issue preventing dialog popups from showing when display driver crashes in some cases.
    • Fixed issue preventing the title in the SimConnect HTML5 window from updating when changed.
    • Fixed crash when deserializing DIS Transimitter PDUs.
    • Added SimDirector VirtualRealityTrigger that can be set to fire when VR is enabled or disabled.
    • Added SimDirector ActionExecutionFilter that can be set to only allow actions to fire if VR is active or not active.

Scenery Fixes and Improvements

    • Fixed various building, vegetation, and vehicle models that would blend incorrectly with clouds.
    • Fixed invalid materials in several vegetation models.
    • Fixed issue that could vehicles to crash with jetways.
    • Updated various airports including W24, KRCW, OMAW, CYUL, and WAVG.

Thanks again for your support!