Windows 11 Build Failing - Multiple Errors on rvmk

[jordanbharris]

Hi everyone — I'm an artist, not a developer, and this is my first time building software from source on Windows. I followed the documentation carefully and got further than I expected, but I'm stuck at the final build step. Any help would be really appreciated!

My Setup:

• OS: Windows 11
• Visual Studio 2022 Community (MSVC 19.40.33821.0)
• MSVC v143 14.40 and 14.39 both installed
• Qt 6.5.3 (msvc2019_64) including WebEngine and Multimedia
• Python 3.11.9
• Strawberry Perl 5.42.2.1
• Rust (latest)
• MSYS2 MINGW64
• CMake 4.3.2 (from C:\Program Files\CMake\bin\cmake.exe)
• VFX Platform: CY2024
• OpenRV branch: main (hash 88d5875)
• Build time: 3 minutes 53 seconds before failure

What's working:
rvcfg completed successfully with the compiler correctly identified as MSVC 19.40.33821.0. Qt, Multimedia and WebEngine all found. So I feel like setup went well! But rvmk fails consistently with the errors below.

Group 1 - cmake_minimum_required compatibility (affects multiple dependencies)

This same error is occurring in at least three separate dependencies: RV_DEPS_ATOMIC_OPS, RV_DEPS_JPEGTURBO, and RV_DEPS_BOOST:

CMake Error at CMakeLists.txt:23 (cmake_minimum_required):
Compatibility with CMake < 3.5 has been removed from CMake.
Update the VERSION argument value. Or, use the ... syntax
to tell CMake that the project requires at least but has been updated
to work with policies introduced by or earlier.
Or, add -DCMAKE_POLICY_VERSION_MINIMUM=3.5 to try configuring anyway.

My suspicion: Could CMake 4.3.2 be too new? The docs specify CMake 3.31.X+ for CY2024. I know CMake 4.0 removed backward compatibility with older scripts — could that be causing this across multiple dependencies?

Error 2 - stdext identifier not found building RV_DEPS_IMGUI:**

C:\Qt\6.5.3\msvc2019_64\include\QtCore\qvarlengtharray.h(379,19): error C3861: 'stdext': identifier not found
C:\Qt\6.5.3\msvc2019_64\include\QtCore\qvarlengtharray.h(379,19): error C2065: 'stdext': undeclared identifier
C:\Qt\6.5.3\msvc2019_64\include\QtCore\qvarlengtharray.h(890,39): error C3861: 'stdext': identifier not found
C:\Qt\6.5.3\msvc2019_64\include\QtCore\qvarlengtharray.h(890,39): error C2065: 'stdext': undeclared identifier
[C:\OpenRV_build\RV_DEPS_IMGUI\build\imgui.vcxproj]

Error 3 - pybind11 configure failure in RV_DEPS_OCIO:

MSB8066: Custom build for pybind11_install-configure.rule exited with code 1.
[C:\OpenRV_build\RV_DEPS_OCIO\build\pybind11_install.vcxproj]

Error 4 - Access Denied building opentimelineio wheel:

CUSTOMBUILD : error : subprocess-exited-with-error
CUSTOMBUILD : error : [WinError 5] Access is denied
CUSTOMBUILD : error : Failed building wheel for opentimelineio
CUSTOMBUILD : error : failed-wheel-build-for-install
[C:\OpenRV_build\cmake\dependencies\RV_DEPS_PYTHON3-stage-target.vcxproj]

This persisted even after relaunching MSYS2 MINGW64 as Administrator.

Total: 15 errors, 1 warning. Build time before failure: 3m 53s.**

What I've already tried:

• Running MSYS2 MINGW64 as Administrator
• Verified MSVC 19.40.X is being used (confirmed in rvcfg output)
• Confirmed Qt WebEngine and Qt Multimedia are both installed

I'm happy to share the full build log if that would help. Thanks so much in advance. I have used RV in multiple productions at studios over the years and it would be great to get it to run on my machine for personal use.

[bernie-laberge]

Hello @jordanbharris !
I believe your suspicion is correct: we've had issues on macOS with CMake >= 4.x.
Best to stick with CMake 3.x (I just checked and I am using CMake 3.31 on my system).
Tip: Claude Code is really useful to debug build issues. I typically use a prompt like:
"Fix build issue reported in /c/orv/OpenRV/_build/build_errors.log"
And our robot friend takes care of finding the root cause. It would be interesting to see if Claude pinpoints the version of CMake as the culprit

[jordanbharris]

Thank you Bernie. Downgrading CMake to 3.11x was the right call, it got me further, but now I have 2 remaining errors.

What's been fixed:

• Downgrading from CMake 4.3.2 to CMake 3.31.12 resolved all the cmake_minimum_required compatibility errors
• The stdext identifier errors in RV_DEPS_IMGUI are also gone
• My antivirus was interfering with the build — I've disabled it during the build and the [WinError 5] Access is denied error is gone
• Total errors are down from 15 to 3

I'm clearly getting much closer. Here are the two remaining errors:

Error 1 - RV_DEPS_BOOST failed with exit code 1:

MSB8066: Custom build for RV_DEPS_BOOST-download.rule ... exited with code 1.
[C:\OpenRV_build\cmake\dependencies\RV_DEPS_BOOST.vcxproj]

The error summary doesn't give a specific reason for the Boost failure — just that it exited with code 1. Happy to dig deeper into the log if you can tell me what to look for.

Error 2 - OverflowError building opentimelineio:

CUSTOMBUILD : error : OverflowError: cannot convert longdouble infinity to integer
[C:\OpenRV_build\cmake\dependencies\RV_DEPS_PYTHON3-stage-target.vcxproj]

This happens during the Python/opentimelineio wheel build. I'm guessing this might be a numpy version compatibility issue on Windows but I honestly don't know.

Current environment (unchanged):

• OS: Windows 11
• Visual Studio 2022 Community (MSVC 19.40.33821.0)
• CMake 3.31.12
• Qt 6.5.3 (msvc2019_64) with WebEngine and Multimedia
• Python 3.11.9
• Strawberry Perl 5.42.2.1
• MSYS2 MINGW64
• VFX Platform: CY2024
• OpenRV branch: main (hash 88d5875)
• Build time before failure: 14 minutes 54 seconds

Full build log available if helpful. Thanks again for the patience with a first-time builder!
And I used Claude to help but it suggested the main problem is environment and tool version compatibility issues. "Those require human judgment and decisions, not just code fixes"

Cheers.

[jordanbharris]

Successfully Built OpenRV on Windows 11 - Fixes and Workarounds Guide

After a lot of troubleshooting with Claude I finally got OpenRV building successfully on Windows 11. I wanted to share the fixes I needed beyond the standard documentation, in case others hit the same walls. None of these are documented anywhere that I could find. Below is a summary of the steps I took...

My Environment:

• Windows 11 Pro
• Visual Studio 2022 Community (MSVC 19.40.33821.0)
• CMake 3.31.12
• Qt 6.5.3 (msvc2019_64) with WebEngine, Multimedia and WebSockets
• Python 3.11.9
• Strawberry Perl 5.42.2.1
• Rust (latest)
• MSYS2 MINGW64
• VFX Platform: CY2024
• OpenRV branch: main

---

Fix 1: Do NOT use CMake 4.x — downgrade to 3.31.x

The CMake website now serves CMake 4.x by default. CMake 4.0 removed backward compatibility with older cmake_minimum_required syntax, which breaks multiple OpenRV dependencies including RV_DEPS_ATOMIC_OPS, RV_DEPS_JPEGTURBO, and RV_DEPS_BOOST with this error:

CMake Error at CMakeLists.txt:23 (cmake_minimum_required):
  Compatibility with CMake < 3.5 has been removed from CMake.

Fix: Download CMake 3.31.x specifically from https://github.com/Kitware/CMake/releases and install that instead. The file you want is cmake-3.31.12-windows-x86_64.msi.

---

Fix 2: Visual Studio 2025 (version 18) is too new — install VS 2022 (version 17) alongside it

If you have Visual Studio 2025 installed, the OpenRV build system won't find it because it looks specifically for "Visual Studio 17 2022". You need to install VS 2022 Community alongside your newer version. They coexist without conflict.

Get the VS 2022 installer directly at: https://aka.ms/vs/17/release/vs_community.exe

Required components:

• Workload: Desktop Development with C++
• Individual Components: MSVC v143 14.40.X and MSVC v143 14.39.X (both marked "out of support" but required)

---

Fix 3: Antivirus will block the build — disable it first

Avast (and likely other antivirus software) will quarantine files mid-build, causing this error:

CUSTOMBUILD : error : [WinError 5] Access is denied
CUSTOMBUILD : error : Failed building wheel for opentimelineio

Fix: Before running rvmk, disable your antivirus real-time protection shields for the duration of the build. Remember to re-enable them when the build is done.

---

Fix 4: Boost bootstrap fails silently because it finds the wrong Visual Studio

The Boost bootstrap script (bootstrap.bat) silently fails on Windows 11 if you have multiple Visual Studio versions installed, because it finds the newer one (VS 2025) instead of VS 2022.

Symptoms: Build fails on RV_DEPS_BOOST with exit code 1, no specific error message.

Fix: Run bootstrap manually from an Administrator CMD prompt:

cd C:\OpenRV\_build\RV_DEPS_BOOST\src
set VS160COMNTOOLS=C:\Program Files\Microsoft Visual Studio\2022\Community\Common7\Tools\
bootstrap.bat --with-toolset=vc143

Then create the configure stamp file to tell the build system this step is done:

touch "/c/OpenRV/_build/cmake/dependencies/RV_DEPS_BOOST-prefix/src/RV_DEPS_BOOST-stamp/Release/RV_DEPS_BOOST-configure"

---

Fix 5: numpy 1.24.4 is hardcoded in CY2024.cmake but has a Windows bug

The CY2024 platform file hardcodes numpy to 1.24.4 which has a known OverflowError: cannot convert longdouble infinity to integer bug on Windows with MSVC.

Fix: Edit cmake/defaults/CY2024.cmake and change the numpy version:

sed -i 's/"1.24.4"/"1.26.4"/' /c/OpenRV/cmake/defaults/CY2024.cmake

Then run rvcfg again before rvmk.

---

Fix 6: PySide6 build fails because make_pyside6.py needs packages not in the venv

The PySide6 build script (src/build/make_pyside6.py) imports from utils.py which requires requests and py7zr. These aren't installed in the OpenRV virtual environment by default.

Fix: Install them into the venv:

/c/OpenRV/.venv/Scripts/python -m pip install requests py7zr

Also install requests into the MSYS2 Python using pacman:

pacman -S mingw-w64-x86_64-python-requests

---

Fix 7: PySide6 must be built from a Visual Studio Developer Command Prompt

This is the biggest non-documented issue. The PySide6 build cannot be run from MSYS2 because cl.exe (the MSVC compiler) isn't in the MSYS2 PATH. Additionally, Strawberry Perl installs its own cmake which gets picked up instead of the correct one, causing Qt to not be found.

Fix: Open Developer Command Prompt for VS 2022 as Administrator, then run:

set PATH=C:\Program Files\CMake\bin;%PATH%
"C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Auxiliary\Build\vcvars64.bat"

Then run the PySide6 build manually:

C:\OpenRV\.venv\Scripts\python C:\OpenRV\src\build\make_pyside6.py --variant Release --source-dir C:\OpenRV\_build\_deps\rv_deps_pyside6-src --output-dir C:\OpenRV\_build\RV_DEPS_PYTHON3\install --temp-dir C:\OpenRV\_build\RV_DEPS_PYTHON3 --openssl-dir C:\OpenRV\_build\RV_DEPS_OPENSSL\install --python-dir C:\OpenRV\_build\RV_DEPS_PYTHON3\install --qt-dir C:\Qt\6.5.3\msvc2019_64 --python-version 3.11 --prepare --build

This will take 30–60 minutes. When it completes, create the PySide6 flag file manually from MINGW64:

touch /c/OpenRV/_build/RV_DEPS_PYTHON3/install/RV_DEPS_PYSIDE6-build-flag

Then run rvmk from MINGW64 as normal — it should complete successfully.

Hope this saves someone else a week of their life! Happy to answer questions.

[cedrik-fuoco-adsk]

Hi @jordanbharris, thank you for taking the time to report back.

I have some comments and questions (for fix 6) on some of the fixes.

---

Fix 1: "Do NOT use CMake 4.x — downgrade to 3.31.x"

The documentation needs to be updated to clearly mention the incompatibility with CMake 4.x. Thank you for flagging this.

---

Fix 2: "VS 2025 is too new — install VS 2022"

While this is correct, the required Visual Studio and MSVC versions for OpenRV and Boost are already mentioned in the Windows documentation. It might need to be more clearly outline though.

---

Fix 3: "Antivirus will block the build"

Thank you for reporting this. Antivirus interference is not something we have been able to reproduce in our builds, but it is a reasonable precaution to be aware of on Windows.

---

Fix 4: "Boost bootstrap fails silently because it finds wrong VS"

Thank you for reporting this. We have not tested extensively with multiple Visual Studio versions installed at the same time.

---

Fix 5: "numpy 1.24.4 is hardcoded in CY2024.cmake and has a Windows bug"

The numpy version for CY2024 must be 1.24.4 to comply with the VFX Reference Platform standard. Rather than editing CY2024.cmake, the correct solution is to switch to CY2025, which already specifies numpy 1.26.4 without deviating from any platform standard.

If you have to stay to CY2024, I doubt there will be any issue with doing this.

---

Fix 6: "PySide6 build fails because requests and py7zr aren't in the venv"

Both requests and py7zr are already listed in requirements.txt and are installed automatically into the virtual environment. The correct fix is to run the rvsetup command, either directly or via rvbootstrap (which runs rvsetup as part of its flow). This command installs all packages listed in requirements.txt, including the two you mentioned.

Two questions @jordanbharris:

1. Did you run either rvbootstrap or rvsetup?
2. Did you install Python through the official installer, or is it using the Python bundled with MSYS2?

The documentation recommends using the official Python installer. No Python packages from MSYS2 are needed.

---

Fix 7: "PySide6 must be built from VS Developer Command Prompt"

This is not necessary. All of our CI and personal Windows builds are done entirely from the MSYS2-MinGW64 shell. The CMake Visual Studio Generator locates the Visual Studio toolchain on its own. cl.exe does not need to be in the MSYS2 PATH.

The Strawberry Perl issue you described (its bundled cmake shadowing the correct one) is already addressed in the documentation: the PATH order in ~/.bash_profile must place Strawberry Perl after MSYS2's mingw64/bin, not before it. Setting up the environment variables correctly as documented is sufficient; no manual invocation from a Visual Studio Developer Command Prompt is needed.

I think it happend to me one time where CMake was not finding the Visual studio Generator. I had to check a checkbox about CMake when installed Visual Studio

[jordanbharris]

Hey @cedrik-fuoco-adsk

Since I am not experienced in the building process I relied heavily on Claude to help me interpret and fix the errors I was getting. It may have had me fix things the long way but eventually I was able to get RV up and running!

Specifically to your questions above Claude said the following regarding the thinking and the process it led me down...

Question 1: Did you run rvbootstrap or rvsetup?
We ran rvsetup but not rvbootstrap. When we sourced rvcmds.sh and selected CY2024, the prompt told us to call rvbootstrap for a first-time build. However we skipped it and went straight to rvcfg followed by rvmk. Everything built successfully without rvbootstrap — though it's possible that's why we had to manually handle some steps like the PySide6 build and stamp files. If someone is following this guide it may be worth trying rvbootstrap first to see if it handles some of those manual steps automatically.

Question 2: Python — official installer or MSYS2?
We used the official Python 3.11.9 installer from python.org. However this caused its own complications — the installer put Python in C:\Users\jbh_studio\AppData\Local\Programs\Python\Python311\ instead of the expected C:\Python311, and the MSYS2 environment kept picking up its own Python 3.14 instead. We had to add an explicit alias in ~/.bash_profile to force the correct Python to be used. The MSYS2 bundled Python was never used for the actual build — only for package management via pacman when we needed to install requests into the MSYS2 environment

Cheers!