Upgrading from UE4.20 to UE4.22.1 "Unable to merge actions producing RMPlayerController.cpp.obj: prerequisites are different"

Development Programming & Scripting
1

I pulled and built the engine in a clean directory, then attempted to convert my project (copy) and received this message. Anyone have tips?

The project could not be compiled. Would you like to open it in Visual Studio?

Running E:/UnrealEngine-4.22.1-clean/Engine/Binaries/DotNET/UnrealBuildTool.exe Development Win64 -Project="D:/RedMarsGame/Application/RedMarsColonizer 4.22/RedMarsColonizer.uproject" -TargetType=Editor -Progress -NoHotReloadFromIDE
Creating makefile for RedMarsColonizerEditor (no existing makefile)
@progress push 5%
Creating makefile for UnrealHeaderTool (no existing makefile)
@progress push 5%
@progress pop
Parsing headers for RedMarsColonizerEditor
  Running UnrealHeaderTool "D:\RedMarsGame\Application\RedMarsColonizer 4.22\RedMarsColonizer.uproject" "D:\RedMarsGame\Application\RedMarsColonizer 4.22\Intermediate\Build\Win64\RedMarsColonizerEditor\Development\RedMarsColonizerEditor.uhtmanifest" -LogCmds="loginit warning, logexit warning, logdatabase error" -Unattended -WarningsAsErrors
Reflection code generated for RedMarsColonizerEditor in 39.0908656 seconds
@progress pop
ERROR: Unable to merge actions producing RMPlayerController.cpp.obj: prerequisites are different
ERROR: Unable to merge actions producing RMPlayerController.cpp.obj: prerequisites are different
ERROR: Action graph is invalid; unable to continue. See log for additional details.
2

Okay, looks like I had somehow copied my .cpp implementation or generated a new one in VS, thus giving me two conflicting copies.

3

Just had a similar problem, with similar solution. But there reason was that i moved files into other folder and saved opened tabs in ide, which cause files duplications at old locations. Hope it helps to someone.