diff --git a/proto-opencl/build.bat b/proto-opencl/build.bat
index 1fa9ac02b..e7a482603 100644
--- a/proto-opencl/build.bat
+++ b/proto-opencl/build.bat
@@ -8,7 +8,7 @@ rem   OCL_ROOT       the old AMD APP SDK layout: %OCL_ROOT%\include and %OCL_ROO
 rem The runtime itself (OpenCL.dll in System32 plus the vendor ICD) comes with the AMD Adrenalin driver; no SDK needed to run.
 rem Usage: build.bat [pack]
 rem   pack  directory name under ..\proto-cuda\packs\ (default igneum-genesis-mh)
-setlocal
+setlocal enabledelayedexpansion
 cd /d "%~dp0"
 
 set PACK=%1
@@ -48,8 +48,27 @@ if "%LIB%"=="" (
 )
 
 echo using headers %INC% and import library %LIB%
-echo cl /nologo /O2 /W3 /std:c11 /I "%INC%" /I "%PACKDIR%" /DIGNEUM_KERNEL_PATH="\"%PACKDIR:\=/%/kernel.cl\"" /Fe:igneum-bench-cl-%PACK%.exe host.c /link "%LIB%"
-cl /nologo /O2 /W3 /std:c11 /I "%INC%" /I "%PACKDIR%" /DIGNEUM_KERNEL_PATH="\"%PACKDIR:\=/%/kernel.cl\"" /Fe:igneum-bench-cl-%PACK%.exe host.c /link "%LIB%"
+rem Find the MSVC runtime libraries and the Windows SDK libraries ourselves, in case the prompt did not set LIB
+rem (seen on a Visual Studio 2026 install where vcvarsall reported success but linking could not find LIBCMT.lib).
+set EXTRALIB=
+set MSVCLIB=
+for /f "delims=" %%D in ('dir /b /ad /o-n "%VCINSTALLDIR%Tools\MSVC" 2^>nul') do (
+  if "!MSVCLIB!"=="" if exist "%VCINSTALLDIR%Tools\MSVC\%%D\lib\x64\libcmt.lib" set MSVCLIB=%VCINSTALLDIR%Tools\MSVC\%%D\lib\x64
+)
+if "%MSVCLIB%"=="" for /f "delims=" %%D in ('dir /b /ad /o-n "C:\Program Files\Microsoft Visual Studio\18\Community\VC\Tools\MSVC" 2^>nul') do (
+  if "!MSVCLIB!"=="" if exist "C:\Program Files\Microsoft Visual Studio\18\Community\VC\Tools\MSVC\%%D\lib\x64\libcmt.lib" set MSVCLIB=C:\Program Files\Microsoft Visual Studio\18\Community\VC\Tools\MSVC\%%D\lib\x64
+)
+set SDKLIB=
+for /f "delims=" %%D in ('dir /b /ad /o-n "C:\Program Files (x86)\Windows Kits\10\Lib" 2^>nul') do (
+  if "!SDKLIB!"=="" if exist "C:\Program Files (x86)\Windows Kits\10\Lib\%%D\ucrt\x64\libucrt.lib" set SDKLIB=C:\Program Files (x86)\Windows Kits\10\Lib\%%D
+)
+if not "%MSVCLIB%"=="" set EXTRALIB=%EXTRALIB% /LIBPATH:"%MSVCLIB%"
+if not "%SDKLIB%"=="" set EXTRALIB=%EXTRALIB% /LIBPATH:"%SDKLIB%\ucrt\x64" /LIBPATH:"%SDKLIB%\um\x64"
+if "%MSVCLIB%"=="" echo warning: could not find libcmt.lib under any MSVC toolset; install "Desktop development with C++" in the Visual Studio Installer.
+if "%SDKLIB%"=="" echo warning: could not find the Windows 10/11 SDK libraries under C:\Program Files ^(x86^)\Windows Kits\10\Lib.
+echo libraries: MSVC=%MSVCLIB% SDK=%SDKLIB%
+echo cl /nologo /O2 /W3 /std:c11 /I "%INC%" /I "%PACKDIR%" /DIGNEUM_KERNEL_PATH="\"%PACKDIR:\=/%/kernel.cl\"" /Fe:igneum-bench-cl-%PACK%.exe host.c /link "%LIB%" %EXTRALIB%
+cl /nologo /O2 /W3 /std:c11 /I "%INC%" /I "%PACKDIR%" /DIGNEUM_KERNEL_PATH="\"%PACKDIR:\=/%/kernel.cl\"" /Fe:igneum-bench-cl-%PACK%.exe host.c /link "%LIB%" %EXTRALIB%
 if errorlevel 1 (
   echo build failed. If cl.exe rejects /std:c11, drop that flag: the code is C99 and MSVC's default C mode accepts it.
   exit /b 1