McStas 3.5.40 Installation Problems

[LelandWH]

System: Microsoft Windows 11 Enterprise
McStas Version: McStas 3.5.40 on Windows 64 bit Intel systems

Below I have copied the first two line-instructions provided by McStas when installing using the new recommended system.
I have added my comments/fixes in Highlighted Text

Recommended:

• Install Visual Studio including c/c++ support. Any recent version of Visual Studio itself should work. Use the "Visual Studio Installer" and modify settings to selecect at minumum "Desktop development with c++" specifying to include VS2019 build tools and CLI support. (It is OK to include build tools such as VS2022 or VS2026, but VS2019 must be present also.
  This line-instruction claims any recent version of Visual Studio will work. However, when I followed the provided link for downloading Visual Studio then I ended up on the Visual Studio 2026 Download page. This version did not work (or at least the Community version did not.) You may want to point explicitly to the 2022 version which can be found on the older downloads page: https://visualstudio.microsoft.com/vs/older-downloads/

• Use the mcstas-conda batch script to install the latest mcstas from conda-forge
  Not sure about other facilities, but where I am at miniforge/microbamba installations are firewalled if you try to pull directly from anaconda.org. Something to do with mitigating the risk of downloading license-encumbered resources (which should not be a problem for the conda-forge channel, but I don't make the rules!). I just changed the micromamba call in the mcstas-conda.bat file to point to the conda-forge mirror that is built and maintained by the developers of micromamba. Namely, I changed:
  @.\micromamba.exe create -n mcstas mcstas -c conda-forge -c nodefaults -y
  to be
  @.\micromamba.exe create -n mcstas mcstas -c https://repo.prefix.dev/conda-forge -c nodefaults -y
  I'm not sure if you want to deal directly with institution specific firewall issues, but thought I would at least mention the issue in case it becomes generally problematic.

[willend]

Hi @LelandWH,

Thanks for reporting. Strangely, I have a completely vanilla VM with Windows 11 arm64 here (runs the x64 conda-forge version) - is functional.

I attach screenshots showing my VS2026 Community and the sub-options selected:

After the installation I used the small utility script mcstas-conda.bat to install 3.5.40.

Here is the output from the conda-shell after installation:

mctest runs - succesfully

and the resulting data look ok:

[LelandWH]

Thanks for the snapshots. That helped me track down the issue.
Namely, I noticed you had both the 2019 and 2020 c++ build tools installed:

I only included the 2019 c++ build tools when I originally installed 2026 Visual Studio.
I just now deleted the 2022 Visual Studio and reverted back to my original 2026 set-up with only 2019 build tools and confirmed McStas breaks, then I included both 2019 and 2022 build tools and it worked. The instructions say "It is OK to include build tools such as VS2022 or VS2026, but VS2019 must be present also." Which implies VS2022 is not required, however I think this may have changed with the 2026 Visual Studio release. Perhaps you can try removing the VS2022 tools on your machine and if McStas breaks for you too then the instructions should be changed to include 2019 and 2022 tools.

[willend]

Thanks for testing.

From the above-mentioned configuration, I

• initially removed the 2019 build tool set - compilation still works
• then removed 2022 and installed 2019 - compilation fails - (but dit not fail until I closed my conda-shell and started anew)

The issue then is that which "minimum" version is required could depend on what route people pick to install mcstas... I.e. using mamba instead of micromamba, a commercial Anaconda installer or something else...

I think I will modify to recommend all MSVC versions in the list from 2019 and up...