Linker error: Unresolved external symbol (but compiles on different machine)

Hi, I am currently on vacation and would like to continue working on my hobby project. I downloaded the current project version, which is created with the UE 5.1, from our github repository, opened the project with the UE 5.1 engine on my laptop and the editor is asking to recompile the project. This is where it fails. It cannot compile the project for some reason. The following error is reported in the logfile:

Building 2 actions with 2 processes…
[1/2] WriteMetadata CastleFightEditor.target cancelled
[2/2] Link UnrealEditor-RealTimeStrategy.dll
Creating library C:\Users\MyName\Documents\GitHub\CastleFight-5.1\Plugins\RealTimeStrategy\Intermediate\Build\Win64\UnrealEditor\Development\RealTimeStrategy\UnrealEditor-RealTimeStrategy.suppressed.lib and object C:\Users\MyName\Documents\GitHub\CastleFight-5.1\Plugins\RealTimeStrategy\Intermediate\Build\Win64\UnrealEditor\Development\RealTimeStrategy\UnrealEditor-RealTimeStrategy.suppressed.exp
Module.RealTimeStrategy.9_of_9.cpp.obj : error LNK2019: unresolved external symbol “public: class TSet<struct TWeakObjectPtr<class URTSFloatingCombatTextComponent,struct FWeakObjectPtr>,struct DefaultKeyFuncs<struct TWeakObjectPtr<class URTSFloatingCombatTextComponent,struct FWeakObjectPtr>,0>,class FDefaultSetAllocator> __cdecl URTSComponentRegistry::GetComponents(void)” (??$GetComponents@VURTSFloatingCombatTextComponent@@@URTSComponentRegistry@@QEAA?AV?$TSet@U?$TWeakObjectPtr@VURTSFloatingCombatTextComponent@@UFWeakObjectPtr@@@@U?$DefaultKeyFuncs@U?$TWeakObjectPtr@VURTSFloatingCombatTextComponent@@UFWeakObjectPtr@@@@$0A@@@VFDefaultSetAllocator@@@@XZ) referenced in function “private: void __cdecl ARTSHUD::DrawFloatingCombatTexts(void)” (?DrawFloatingCombatTexts@ARTSHUD@@AEAAXXZ)

Module.RealTimeStrategy.9_of_9.cpp.obj : error LNK2019: unresolved external symbol “public: class TSet<struct TWeakObjectPtr<class URTSHealthBarWidgetComponent,struct FWeakObjectPtr>,struct DefaultKeyFuncs<struct TWeakObjectPtr<class URTSHealthBarWidgetComponent,struct FWeakObjectPtr>,0>,class FDefaultSetAllocator> __cdecl URTSComponentRegistry::GetComponents(void)” (??$GetComponents@VURTSHealthBarWidgetComponent@@@URTSComponentRegistry@@QEAA?AV?$TSet@U?$TWeakObjectPtr@VURTSHealthBarWidgetComponent@@UFWeakObjectPtr@@@@U?$DefaultKeyFuncs@U?$TWeakObjectPtr@VURTSHealthBarWidgetComponent@@UFWeakObjectPtr@@@@$0A@@@VFDefaultSetAllocator@@@@XZ) referenced in function "private: void __cdecl ARTSHUD::DrawHealthBars(void)const " (?DrawHealthBars@ARTSHUD@@AEBAXXZ)

Module.RealTimeStrategy.9_of_9.cpp.obj : error LNK2019: unresolved external symbol “public: class TSet<struct TWeakObjectPtr<class URTSConstructionProgressBarWidgetComponent,struct FWeakObjectPtr>,struct DefaultKeyFuncs<struct TWeakObjectPtr<class URTSConstructionProgressBarWidgetComponent,struct FWeakObjectPtr>,0>,class FDefaultSetAllocator> __cdecl URTSComponentRegistry::GetComponents(void)” (??$GetComponents@VURTSConstructionProgressBarWidgetComponent@@@URTSComponentRegistry@@QEAA?AV?$TSet@U?$TWeakObjectPtr@VURTSConstructionProgressBarWidgetComponent@@UFWeakObjectPtr@@@@U?$DefaultKeyFuncs@U?$TWeakObjectPtr@VURTSConstructionProgressBarWidgetComponent@@UFWeakObjectPtr@@@@$0A@@@VFDefaultSetAllocator@@@@XZ) referenced in function "private: void __cdecl ARTSHUD::DrawConstructionProgressBars(void)const " (?DrawConstructionProgressBars@ARTSHUD@@AEBAXXZ)

Module.RealTimeStrategy.9_of_9.cpp.obj : error LNK2019: unresolved external symbol “public: class TSet<struct TWeakObjectPtr<class URTSProductionProgressBarWidgetComponent,struct FWeakObjectPtr>,struct DefaultKeyFuncs<struct TWeakObjectPtr<class URTSProductionProgressBarWidgetComponent,struct FWeakObjectPtr>,0>,class FDefaultSetAllocator> __cdecl URTSComponentRegistry::GetComponents(void)” (??$GetComponents@VURTSProductionProgressBarWidgetComponent@@@URTSComponentRegistry@@QEAA?AV?$TSet@U?$TWeakObjectPtr@VURTSProductionProgressBarWidgetComponent@@UFWeakObjectPtr@@@@U?$DefaultKeyFuncs@U?$TWeakObjectPtr@VURTSProductionProgressBarWidgetComponent@@UFWeakObjectPtr@@@@$0A@@@VFDefaultSetAllocator@@@@XZ) referenced in function "private: void __cdecl ARTSHUD::DrawProductionProgressBars(void)const " (?DrawProductionProgressBars@ARTSHUD@@AEBAXXZ)
C:\Users\MyName\Documents\GitHub\CastleFight-5.1\Plugins\RealTimeStrategy\Binaries\Win64\UnrealEditor-RealTimeStrategy.dll : fatal error LNK1120: 4 unresolved externals

RealTimeStrategy is a plugin we use for the RTS-like game we are currently working on. I cannot tell by the error message which files are actually causing the issue. I looked into a few of the files but could not find the function names mentioned in the error message. The project compiled just fine on my home computer. Anyone got advice on how to proceed? I would love to continue working on the project on my vacation :slight_smile: