Separate Debug and Release .dcu output. Not doing so can confuse Delphi. You should delete all *.dpr dirs you already have in the root of the two Dcu folders. Also some other cleanup to both compile.bat's.

ISHelp/ISHelpGen/ISHelpGen.dproj

@@ -46,7 +46,6 @@
         <DCC_EXPLICIT_STRING_CAST_LOSS>false</DCC_EXPLICIT_STRING_CAST_LOSS>
         <DCC_IMPLICIT_INTEGER_CAST_LOSS>false</DCC_IMPLICIT_INTEGER_CAST_LOSS>
         <DCC_IMPLICIT_CONVERSION_LOSS>false</DCC_IMPLICIT_CONVERSION_LOSS>
-        <DCC_DcuOutput>Dcu\$(MainSource)</DCC_DcuOutput>
     </PropertyGroup>
     <PropertyGroup Condition="'$(Base_Win32)'!=''">
         <DCC_Namespace>Winapi;System.Win;Data.Win;Datasnap.Win;Web.Win;Soap.Win;Xml.Win;Bde;$(DCC_Namespace)</DCC_Namespace>
@@ -58,11 +57,13 @@
         <DCC_Define>RELEASE;$(DCC_Define)</DCC_Define>
         <DCC_DebugInformation>0</DCC_DebugInformation>
         <DCC_LocalDebugSymbols>false</DCC_LocalDebugSymbols>
+        <DCC_DcuOutput>Dcu\Release\$(MainSource)</DCC_DcuOutput>
     </PropertyGroup>
     <PropertyGroup Condition="'$(Cfg_2)'!=''">
         <DCC_Define>DEBUG;$(DCC_Define)</DCC_Define>
         <DCC_Optimize>false</DCC_Optimize>
         <DCC_GenerateStackFrames>true</DCC_GenerateStackFrames>
+        <DCC_DcuOutput>Dcu\Debug\$(MainSource)</DCC_DcuOutput>
         <Debugger_RunParams>..</Debugger_RunParams>
     </PropertyGroup>
     <ItemGroup>

ISHelp/ISHelpGen/compile.bat

@@ -1,7 +1,7 @@
 @echo off
 
 rem  Inno Setup
-rem  Copyright (C) 1997-2022 Jordan Russell
+rem  Copyright (C) 1997-2025 Jordan Russell
 rem  Portions by Martijn Laan
 rem  For conditions of distribution and use, see LICENSE.TXT.
 rem
@@ -22,12 +22,19 @@ set DELPHIXEROOT=
 call .\compilesettings.bat
 if "%DELPHIXEROOT%"=="" goto compilesettingserror
 
+set DELPHIXELIB=%DELPHIXEROOT%\lib\win32\release
+
 rem -------------------------------------------------------------------------
 
 set DELPHIXEDISABLEDWARNINGS=-W-SYMBOL_DEPRECATED -W-SYMBOL_PLATFORM -W-UNSAFE_CAST -W-EXPLICIT_STRING_CAST -W-EXPLICIT_STRING_CAST_LOSS -W-IMPLICIT_INTEGER_CAST_LOSS -W-IMPLICIT_CONVERSION_LOSS
 
+set FLAGS=--no-config -Q -B -$L- -$C- -H -W %DELPHIXEDISABLEDWARNINGS% %1
+set NAMESPACES=System;System.Win;Winapi
+set DCUDIR=Dcu\Release
+
 echo Compiling ISHelpGen.dpr:
-"%DELPHIXEROOT%\bin\dcc32.exe" --no-config -NSsystem;system.win;winapi -Q -B -H -W %DELPHIXEDISABLEDWARNINGS% %1 -U"%DELPHIXEROOT%\lib\win32\release" ISHelpGen.dpr
+mkdir %DCUDIR%\ISHelpGen.dpr 2>nul
+"%DELPHIXEROOT%\bin\dcc32.exe" %FLAGS% -NS%NAMESPACES% -U"%DELPHIXELIB%" -NU%DCUDIR%\ISHelpGen.dpr ISHelpGen.dpr
 if errorlevel 1 goto failed
 
 echo Success!

Projects/Compil32.dproj

@@ -50,7 +50,6 @@
         <DCC_EXPLICIT_STRING_CAST_LOSS>false</DCC_EXPLICIT_STRING_CAST_LOSS>
         <DCC_IMPLICIT_INTEGER_CAST_LOSS>false</DCC_IMPLICIT_INTEGER_CAST_LOSS>
         <DCC_IMPLICIT_CONVERSION_LOSS>false</DCC_IMPLICIT_CONVERSION_LOSS>
-        <DCC_DcuOutput>Dcu\$(MainSource)</DCC_DcuOutput>
     </PropertyGroup>
     <PropertyGroup Condition="'$(Base_Win32)'!=''">
         <BT_BuildType>Debug</BT_BuildType>
@@ -63,12 +62,14 @@
         <DCC_Define>RELEASE;$(DCC_Define)</DCC_Define>
         <DCC_DebugInformation>0</DCC_DebugInformation>
         <DCC_LocalDebugSymbols>false</DCC_LocalDebugSymbols>
+        <DCC_DcuOutput>Dcu\Release\$(MainSource)</DCC_DcuOutput>
         <DCC_ExeOutput>..\Files</DCC_ExeOutput>
     </PropertyGroup>
     <PropertyGroup Condition="'$(Cfg_2)'!=''">
         <DCC_Define>DEBUG;$(DCC_Define)</DCC_Define>
         <DCC_Optimize>false</DCC_Optimize>
         <DCC_GenerateStackFrames>true</DCC_GenerateStackFrames>
+        <DCC_DcuOutput>Dcu\Debug\$(MainSource)</DCC_DcuOutput>
         <DCC_ExeOutput>Bin</DCC_ExeOutput>
         <Debugger_RunParams>Debug.iss</Debugger_RunParams>
     </PropertyGroup>

Projects/ISCC.dproj

@@ -51,7 +51,6 @@
         <DCC_EXPLICIT_STRING_CAST_LOSS>false</DCC_EXPLICIT_STRING_CAST_LOSS>
         <DCC_IMPLICIT_INTEGER_CAST_LOSS>false</DCC_IMPLICIT_INTEGER_CAST_LOSS>
         <DCC_IMPLICIT_CONVERSION_LOSS>false</DCC_IMPLICIT_CONVERSION_LOSS>
-        <DCC_DcuOutput>Dcu\$(MainSource)</DCC_DcuOutput>
     </PropertyGroup>
     <PropertyGroup Condition="'$(Base_Win32)'!=''">
         <BT_BuildType>Debug</BT_BuildType>
@@ -62,12 +61,14 @@
         <DCC_Define>RELEASE;$(DCC_Define)</DCC_Define>
         <DCC_DebugInformation>0</DCC_DebugInformation>
         <DCC_LocalDebugSymbols>false</DCC_LocalDebugSymbols>
+        <DCC_DcuOutput>Dcu\Release\$(MainSource)</DCC_DcuOutput>
         <DCC_ExeOutput>..\Files</DCC_ExeOutput>
     </PropertyGroup>
     <PropertyGroup Condition="'$(Cfg_2)'!=''">
         <DCC_Define>DEBUG;$(DCC_Define)</DCC_Define>
         <DCC_Optimize>false</DCC_Optimize>
         <DCC_GenerateStackFrames>true</DCC_GenerateStackFrames>
+        <DCC_DcuOutput>Dcu\Debug\$(MainSource)</DCC_DcuOutput>
         <DCC_ExeOutput>Bin</DCC_ExeOutput>
         <Debugger_RunParams>Debug.iss</Debugger_RunParams>
     </PropertyGroup>

Projects/ISCmplr.dproj

@@ -51,7 +51,6 @@
         <DCC_EXPLICIT_STRING_CAST_LOSS>false</DCC_EXPLICIT_STRING_CAST_LOSS>
         <DCC_IMPLICIT_INTEGER_CAST_LOSS>false</DCC_IMPLICIT_INTEGER_CAST_LOSS>
         <DCC_IMPLICIT_CONVERSION_LOSS>false</DCC_IMPLICIT_CONVERSION_LOSS>
-        <DCC_DcuOutput>Dcu\$(MainSource)</DCC_DcuOutput>
     </PropertyGroup>
     <PropertyGroup Condition="'$(Base_Win32)'!=''">
         <BT_BuildType>Debug</BT_BuildType>
@@ -64,12 +63,14 @@
         <DCC_DebugInformation>0</DCC_DebugInformation>
         <DCC_LocalDebugSymbols>false</DCC_LocalDebugSymbols>
         <DCC_SymbolReferenceInfo>0</DCC_SymbolReferenceInfo>
+        <DCC_DcuOutput>Dcu\Release\$(MainSource)</DCC_DcuOutput>
         <DCC_ExeOutput>..\Files</DCC_ExeOutput>
     </PropertyGroup>
     <PropertyGroup Condition="'$(Cfg_2)'!=''">
         <DCC_Define>DEBUG;$(DCC_Define)</DCC_Define>
         <DCC_Optimize>false</DCC_Optimize>
         <DCC_GenerateStackFrames>true</DCC_GenerateStackFrames>
+        <DCC_DcuOutput>Dcu\Debug\$(MainSource)</DCC_DcuOutput>
         <DCC_ExeOutput>Bin</DCC_ExeOutput>
         <Debugger_HostApplication>Bin\Compil32.exe</Debugger_HostApplication>
         <Debugger_RunParams>Debug.iss</Debugger_RunParams>

Projects/ISPP.dproj

@@ -49,7 +49,6 @@
         <DCC_EXPLICIT_STRING_CAST_LOSS>false</DCC_EXPLICIT_STRING_CAST_LOSS>
         <DCC_IMPLICIT_INTEGER_CAST_LOSS>false</DCC_IMPLICIT_INTEGER_CAST_LOSS>
         <DCC_IMPLICIT_CONVERSION_LOSS>false</DCC_IMPLICIT_CONVERSION_LOSS>
-        <DCC_DcuOutput>Dcu\$(MainSource)</DCC_DcuOutput>
     </PropertyGroup>
     <PropertyGroup Condition="'$(Base_Win32)'!=''">
         <BT_BuildType>Debug</BT_BuildType>
@@ -62,12 +61,14 @@
         <DCC_DebugInformation>0</DCC_DebugInformation>
         <DCC_LocalDebugSymbols>false</DCC_LocalDebugSymbols>
         <DCC_SymbolReferenceInfo>0</DCC_SymbolReferenceInfo>
+        <DCC_DcuOutput>Dcu\Release\$(MainSource)</DCC_DcuOutput>
         <DCC_ExeOutput>..\Files</DCC_ExeOutput>
     </PropertyGroup>
     <PropertyGroup Condition="'$(Cfg_2)'!=''">
         <DCC_Define>DEBUG;$(DCC_Define)</DCC_Define>
         <DCC_Optimize>false</DCC_Optimize>
         <DCC_GenerateStackFrames>true</DCC_GenerateStackFrames>
+        <DCC_DcuOutput>Dcu\Debug\$(MainSource)</DCC_DcuOutput>
         <DCC_ExeOutput>Bin</DCC_ExeOutput>
         <Debugger_HostApplication>Bin\Compil32.exe</Debugger_HostApplication>
         <Debugger_RunParams>Debug.iss</Debugger_RunParams>

Projects/ISSigTool.dproj

@@ -49,7 +49,6 @@
         <DCC_EXPLICIT_STRING_CAST_LOSS>false</DCC_EXPLICIT_STRING_CAST_LOSS>
         <DCC_IMPLICIT_INTEGER_CAST_LOSS>false</DCC_IMPLICIT_INTEGER_CAST_LOSS>
         <DCC_IMPLICIT_CONVERSION_LOSS>false</DCC_IMPLICIT_CONVERSION_LOSS>
-        <DCC_DcuOutput>Dcu\$(MainSource)</DCC_DcuOutput>
     </PropertyGroup>
     <PropertyGroup Condition="'$(Base_Win32)'!=''">
         <BT_BuildType>Debug</BT_BuildType>
@@ -60,12 +59,14 @@
         <DCC_Define>RELEASE;$(DCC_Define)</DCC_Define>
         <DCC_DebugInformation>0</DCC_DebugInformation>
         <DCC_LocalDebugSymbols>false</DCC_LocalDebugSymbols>
+        <DCC_DcuOutput>Dcu\Release\$(MainSource)</DCC_DcuOutput>
         <DCC_ExeOutput>..\Files</DCC_ExeOutput>
     </PropertyGroup>
     <PropertyGroup Condition="'$(Cfg_2)'!=''">
         <DCC_Define>DEBUG;$(DCC_Define)</DCC_Define>
         <DCC_Optimize>false</DCC_Optimize>
         <DCC_GenerateStackFrames>true</DCC_GenerateStackFrames>
+        <DCC_DcuOutput>Dcu\Debug\$(MainSource)</DCC_DcuOutput>
         <DCC_ExeOutput>Bin</DCC_ExeOutput>
     </PropertyGroup>
     <ItemGroup>

Projects/Setup.dproj

@@ -47,7 +47,6 @@
         <DCC_EXPLICIT_STRING_CAST_LOSS>false</DCC_EXPLICIT_STRING_CAST_LOSS>
         <DCC_IMPLICIT_INTEGER_CAST_LOSS>false</DCC_IMPLICIT_INTEGER_CAST_LOSS>
         <DCC_IMPLICIT_CONVERSION_LOSS>false</DCC_IMPLICIT_CONVERSION_LOSS>
-        <DCC_DcuOutput>Dcu\$(MainSource)</DCC_DcuOutput>
     </PropertyGroup>
     <PropertyGroup Condition="'$(Base_Win32)'!=''">
         <BT_BuildType>Debug</BT_BuildType>
@@ -61,12 +60,14 @@
         <DCC_Define>RELEASE;$(DCC_Define)</DCC_Define>
         <DCC_DebugInformation>0</DCC_DebugInformation>
         <DCC_LocalDebugSymbols>false</DCC_LocalDebugSymbols>
+        <DCC_DcuOutput>Dcu\Release\$(MainSource)</DCC_DcuOutput>
         <DCC_ExeOutput>..\Files</DCC_ExeOutput>
     </PropertyGroup>
     <PropertyGroup Condition="'$(Cfg_2)'!=''">
         <DCC_Define>DEBUG;$(DCC_Define)</DCC_Define>
         <DCC_Optimize>false</DCC_Optimize>
         <DCC_GenerateStackFrames>true</DCC_GenerateStackFrames>
+        <DCC_DcuOutput>Dcu\Debug\$(MainSource)</DCC_DcuOutput>
         <DCC_ExeOutput>Bin</DCC_ExeOutput>
         <Debugger_RunParams>/LOG=Setup.log</Debugger_RunParams>
     </PropertyGroup>

Projects/SetupLdr.dproj

@@ -45,7 +45,6 @@
         <DCC_EXPLICIT_STRING_CAST_LOSS>false</DCC_EXPLICIT_STRING_CAST_LOSS>
         <DCC_IMPLICIT_INTEGER_CAST_LOSS>false</DCC_IMPLICIT_INTEGER_CAST_LOSS>
         <DCC_IMPLICIT_CONVERSION_LOSS>false</DCC_IMPLICIT_CONVERSION_LOSS>
-        <DCC_DcuOutput>Dcu\$(MainSource)</DCC_DcuOutput>
         <DCC_Define>SETUPLDRPROJ;$(DCC_Define)</DCC_Define>
     </PropertyGroup>
     <PropertyGroup Condition="'$(Base_Win32)'!=''">
@@ -59,12 +58,14 @@
         <DCC_Define>RELEASE;$(DCC_Define)</DCC_Define>
         <DCC_DebugInformation>0</DCC_DebugInformation>
         <DCC_LocalDebugSymbols>false</DCC_LocalDebugSymbols>
+        <DCC_DcuOutput>Dcu\Release\$(MainSource)</DCC_DcuOutput>
         <DCC_ExeOutput>..\Files</DCC_ExeOutput>
     </PropertyGroup>
     <PropertyGroup Condition="'$(Cfg_2)'!=''">
         <DCC_Define>DEBUG;$(DCC_Define)</DCC_Define>
         <DCC_Optimize>false</DCC_Optimize>
         <DCC_GenerateStackFrames>true</DCC_GenerateStackFrames>
+        <DCC_DcuOutput>Dcu\Debug\$(MainSource)</DCC_DcuOutput>
         <DCC_ExeOutput>Bin</DCC_ExeOutput>
     </PropertyGroup>
     <ItemGroup>

compile.bat

@@ -34,10 +34,11 @@ rem  if multiple projects are specified on the command line.
 
 set DELPHIXEDISABLEDWARNINGS=-W-SYMBOL_DEPRECATED -W-SYMBOL_PLATFORM -W-UNSAFE_CAST -W-EXPLICIT_STRING_CAST -W-EXPLICIT_STRING_CAST_LOSS -W-IMPLICIT_INTEGER_CAST_LOSS -W-IMPLICIT_CONVERSION_LOSS
 
-set STANDARDFLAGS=--no-config -Q -B -$L- -$C- -H -W %DELPHIXEDISABLEDWARNINGS% %1 -E..\Files
-set STANDARDFLAGSCONSOLE=%STANDARDFLAGS% -CC
-set STANDARDFLAGSE32=%STANDARDFLAGS% -TX.e32
-set STANDARDNAMESPACES=System;System.Win;Winapi
+set FLAGS=--no-config -Q -B -$L- -$C- -H -W %DELPHIXEDISABLEDWARNINGS% %1 -E..\Files
+set FLAGSCONSOLE=%FLAGS% -CC
+set FLAGSE32=%FLAGS% -TX.e32
+set NAMESPACES=System;System.Win;Winapi
+set DCUDIR=Dcu\Release
 
 set ROPSSRC=..\Components\UniPS\Source
 set ROPSDEF=PS_MINIVCL;PS_NOGRAPHCONST;PS_PANSICHAR;PS_NOINTERFACEGUIDBRACKETS
@@ -49,39 +50,39 @@ if "%1"=="issigtool" goto issigtool
 if not "%1"=="" goto failed
 
 echo - ISPP.dpr
-mkdir Dcu\ISPP.dpr 2>nul
-"%DELPHIXEROOT%\bin\dcc32.exe" %STANDARDFLAGSCONSOLE% -NS%STANDARDNAMESPACES%  -U"%DELPHIXELIB%"  -NUDcu\ISPP.dpr ISPP.dpr
+mkdir %DCUDIR%\ISPP.dpr 2>nul
+"%DELPHIXEROOT%\bin\dcc32.exe" %FLAGSCONSOLE% -NS%NAMESPACES%  -U"%DELPHIXELIB%"  -NU%DCUDIR%\ISPP.dpr ISPP.dpr
 if errorlevel 1 goto failed
 
 echo - Compil32.dpr
-mkdir Dcu\Compil32.dpr 2>nul
-"%DELPHIXEROOT%\bin\dcc32.exe" %STANDARDFLAGS% -NS%STANDARDNAMESPACES%;Vcl;Vcl.Imaging -U"%DELPHIXELIB%;%ROPSSRC%" -NUDcu\Compil32.dpr -DCOMPIL32PROJ;%ROPSDEF% Compil32.dpr
+mkdir %DCUDIR%\Compil32.dpr 2>nul
+"%DELPHIXEROOT%\bin\dcc32.exe" %FLAGS% -NS%NAMESPACES%;Vcl;Vcl.Imaging -U"%DELPHIXELIB%;%ROPSSRC%" -NU%DCUDIR%\Compil32.dpr -DCOMPIL32PROJ;%ROPSDEF% Compil32.dpr
 if errorlevel 1 goto failed
 
 echo - ISCC.dpr
-mkdir Dcu\ISCC.dpr 2>nul
-"%DELPHIXEROOT%\bin\dcc32.exe" %STANDARDFLAGS% -NS%STANDARDNAMESPACES% -U"%DELPHIXELIB%;%ROPSSRC%" -NUDcu\ISCC.dpr -D%ROPSDEF% ISCC.dpr
+mkdir %DCUDIR%\ISCC.dpr 2>nul
+"%DELPHIXEROOT%\bin\dcc32.exe" %FLAGS% -NS%NAMESPACES% -U"%DELPHIXELIB%;%ROPSSRC%" -NU%DCUDIR%\ISCC.dpr -D%ROPSDEF% ISCC.dpr
 if errorlevel 1 goto failed
 
 echo - ISCmplr.dpr
-mkdir Dcu\ISCmplr.dpr 2>nul
-"%DELPHIXEROOT%\bin\dcc32.exe" %STANDARDFLAGS% -NS%STANDARDNAMESPACES% -U"%DELPHIXELIB%;%ROPSSRC%" -NUDcu\ISCmplr.dpr -D%ROPSDEF% ISCmplr.dpr
+mkdir %DCUDIR%\ISCmplr.dpr 2>nul
+"%DELPHIXEROOT%\bin\dcc32.exe" %FLAGS% -NS%NAMESPACES% -U"%DELPHIXELIB%;%ROPSSRC%" -NU%DCUDIR%\ISCmplr.dpr -D%ROPSDEF% ISCmplr.dpr
 if errorlevel 1 goto failed
 
 echo - SetupLdr.dpr
-mkdir Dcu\SetupLdr.dpr 2>nul
-"%DELPHIXEROOT%\bin\dcc32.exe" %STANDARDFLAGSE32% -NS%STANDARDNAMESPACES% -U"%DELPHIXELIB%" -NUDcu\SetupLdr.dpr -DSETUPLDRPROJ SetupLdr.dpr
+mkdir %DCUDIR%\SetupLdr.dpr 2>nul
+"%DELPHIXEROOT%\bin\dcc32.exe" %FLAGSE32% -NS%NAMESPACES% -U"%DELPHIXELIB%" -NU%DCUDIR%\SetupLdr.dpr -DSETUPLDRPROJ SetupLdr.dpr
 if errorlevel 1 goto failed
 
 echo - Setup.dpr
-mkdir Dcu\Setup.dpr 2>nul
-"%DELPHIXEROOT%\bin\dcc32.exe" %STANDARDFLAGSE32% -NS%STANDARDNAMESPACES%;Vcl -U"%DELPHIXELIB%;%ROPSSRC%" -NUDcu\Setup.dpr -DSETUPPROJ;%ROPSDEF% Setup.dpr
+mkdir %DCUDIR%\Setup.dpr 2>nul
+"%DELPHIXEROOT%\bin\dcc32.exe" %FLAGSE32% -NS%NAMESPACES%;Vcl -U"%DELPHIXELIB%;%ROPSSRC%" -NU%DCUDIR%\Setup.dpr -DSETUPPROJ;%ROPSDEF% Setup.dpr
 if errorlevel 1 goto failed
 
 :issigtool
 echo - ISSigTool.dpr
-mkdir Dcu\ISSigTool.dpr 2>nul
-"%DELPHIXEROOT%\bin\dcc32.exe" %STANDARDFLAGSCONSOLE% -NS%STANDARDNAMESPACES% -U"%DELPHIXELIB%" -NUDcu\ISSigTool.dpr ISSigTool.dpr
+mkdir %DCUDIR%\ISSigTool.dpr 2>nul
+"%DELPHIXEROOT%\bin\dcc32.exe" %FLAGSCONSOLE% -NS%NAMESPACES% -U"%DELPHIXELIB%" -NU%DCUDIR%\ISSigTool.dpr ISSigTool.dpr
 if errorlevel 1 goto failed
 
 cd ..