Health-GPS
Global Health Policy Simulation model
Windows MSVC / Ninja build troubleshooting
Global Health Policy Simulation model
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Last updated: July 2026
Why I wrote this
A Windows Visual Studio build that had been fine for weeks suddenly failed on configure and compile. Nothing in the Health-GPS source had changed. The problem was the local MSVC toolchain: a broken toolset install, plus Ninja needing a proper developer environment.
This is not a bug in Health-GPS. The presets and code were fine. I am writing down what went wrong and how to get unstuck so nobody on the team wastes another afternoon on it.
Related documentation
| Topic | Document |
|---|---|
| Normal build steps | Developer Guide |
| Developer docs | developer/README.md |
| Technical guides and plans | technical/README.md |
| Documentation index | documentation/README.md |
| Quick start (binaries) | Quick Start |
Table of contents
- Symptoms
- Root causes
- How I diagnosed it
- What fixed it
- Checklist for next time
- Repairing Visual Studio properly
- What it was not
1. Symptoms
I hit three related errors. They look different in the CMake output, but they are the same class of problem.
Error A: missing standard header
fatal error C1083: Cannot open include file: 'cstdint': No such file or directory
Same idea for <algorithm>, <functional>, <optional>, and friends. Easy to blame a project include path. That was a red herring.
Error B: CMake cannot find the compiler
-- The CXX compiler identification is unknown
CMake Error: No CMAKE_CXX_COMPILER could be found.
Visual Studio ran CMake without a usable MSVC environment (INCLUDE / PATH for cl.exe missing).
Error C: compiler found, CMake test link fails
-- The CXX compiler identification is MSVC 19.42.x
-- Check for working CXX compiler: ...\14.42.34433\...\cl.exe - broken
LINK : fatal error LNK1104: cannot open file 'MSVCRTD.lib'
This one was the giveaway. cl.exe was on disk, but the x64 runtime libs for that toolset were missing.
2. Root causes
2.1 Ninja needs the MSVC developer environment
Health-GPS uses the Ninja generator on Windows (CMakePresets.json). With Ninja, MSVC leans on environment variables from vcvars64.bat (or Visual Studio’s equivalent):
INCLUDE: standard headers (cstdint, etc.)LIB: runtime import libraries (MSVCRTD.lib, etc.)PATH:cl.exe,link.exe
Without that environment you get Error A or Error B.
2.2 Broken toolset on disk
I had more than one MSVC toolset under:
C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\
| Toolset | x64 MSVCRTD.lib |
|---|---|
| 14.42.34433 | Missing (lib\x64 empty or incomplete) |
| 14.44.35207 | Present |
Visual Studio / CMake preferred 14.42, so linking failed even though 14.44 was fine. That fits a partial VS update leaving an older toolset half-installed.
vcpkg also found a compiler binary. That does not mean the active toolset’s libs are intact.
3. How I diagnosed it
- Confirmed
#include <cstdint>in our headers is normal and correct. - Compared CMake environment dumps:
- First run: no
INCLUDE/LIB-> Errors B / A. - Later run (from Native Tools):
INCLUDEpresent, butLIBpointed at the broken 14.42 tree -> Error C.
- First run: no
- Checked on disk:
dir "C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.42.34433\lib\x64\msvcrtd.lib"
dir "C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC\14.44.35207\lib\x64\msvcrtd.lib"
- Forced the healthy toolset:
call "C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Auxiliary\Build\vcvars64.bat" -vcvars_ver=14.44.35207
After that, LIB included ...\MSVC\14.44.35207\lib\x64, CMake configured, and the release build completed.
4. What fixed it
No Health-GPS code or CMake preset edits were needed.
Immediate recovery
- Close Visual Studio.
- Open x64 Native Tools Command Prompt for VS 2022.
- Initialise the toolset that actually has
lib\x64\msvcrtd.lib(on my machine:14.44.35207):
call "C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Auxiliary\Build\vcvars64.bat" -vcvars_ver=14.44.35207
cd /d C:\HealthGPS
- Clear a stale configure cache if needed:
rmdir /s /q out\build\windows-release
- Reconfigure and build:
cmake --preset windows-release
cmake --build out\build\windows-release
- To keep working in the IDE with the same environment:
devenv C:\HealthGPS
Then pick windows-release and Build -> Build All. Avoid “Delete Cache and Reconfigure” from a normal devenv launch that still defaults to the broken 14.42 toolset.
What success looks like
-- The CXX compiler identification is MSVC ...
-- Check for working CXX compiler: ...\14.44.35207\...\cl.exe - skipped
-- Configuring done
-- Generating done
Binary:
out\build\windows-release\src\HealthGPS.Console\HealthGPS.Console.exe
5. Checklist for next time
| Step | Action |
|---|---|
| 1 | Confirm it is not a source change. Does a clean clone of main fail the same way? |
| 2 | Use x64 Native Tools Command Prompt, not a plain PowerShell or terminal. |
| 3 | Check echo %INCLUDE% and echo %LIB%. Both should be set, and LIB should include an MSVC\14.xx...\lib\x64 path. |
| 4 | Confirm msvcrtd.lib exists under that lib\x64 folder. |
| 5 | If missing, list other toolsets under VC\Tools\MSVC\ and retry with -vcvars_ver=<good-version>. |
| 6 | Delete out\build\windows-release (or your preset folder) and reconfigure. |
| 7 | If several toolsets look broken, run Visual Studio Installer -> Repair (section 6). |
| 8 | Only after the toolchain works should you dig into project CMake or source. Usually you will not need to. |
Handy commands
:: Which toolsets exist?
dir "C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC"
:: Does any toolset have the debug CRT import lib?
where /R "C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Tools\MSVC" msvcrtd.lib
6. Repairing Visual Studio properly
-vcvars_ver= is fine for a day. I still prefer a clean install so Visual Studio defaults to a healthy toolset.
- Open Visual Studio Installer.
- Select Visual Studio Community 2022 -> Repair.
- If it still fails, Modify -> Individual components:
- Install MSVC v143 - VS 2022 C++ x64/x86 build tools (Latest).
- Install a Windows 10/11 SDK.
- Optionally remove a clearly broken older 14.42 (or similar) component if Repair left it incomplete.
- Reboot if prompted.
- Open a fresh x64 Native Tools prompt, confirm
LIBpoints at a toolset withlib\x64\msvcrtd.lib, then reconfigure Health-GPS.
After a good Repair, opening the folder in Visual Studio normally should work again without -vcvars_ver.
7. What it was not
| Suspect | Why I ruled it out |
|---|---|
Health-GPS #include <cstdint> |
Correct; only fails when MSVC headers are invisible. |
| Broken CMakePresets | Presets were fine; environment / toolset was not. |
| vcpkg registry warnings | Noise; packages installed successfully. |
| Missing project code | Full release build worked once 14.44 was active. |
Questions?
If you see cstdint, CMAKE_CXX_COMPILER, or MSVCRTD.lib errors on Windows, start here and with the Developer Guide. If your machine shows a different broken toolset version, contact me (Mahima Ghosh) and we can note that case here too.
July 2026. Windows MSVC / Ninja environment failure on my Health-GPS machine; fixed by switching to a complete MSVC 14.44 toolset and repairing Visual Studio.
Author: Mahima Ghosh