diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 137777f825..15440d15b2 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -444,17 +444,17 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - desc: MacOS-11
-            runner: macos-11
-            nametag: macos11-py39
-            cc_compiler: /usr/local/opt/llvm@14/bin/clang
-            cxx_compiler: /usr/local/opt/llvm@14/bin/clang++
-            cxx_std: 17
-            python_ver: "3.10"
-            aclang: 13
-            setenvs: export LLVMBREWVER="@14" DO_BREW_UPDATE=1
-                            OPENIMAGEIO_VERSION=release
-                            QT_BREW_VERSION="@5"
+          # - desc: MacOS-11
+          #   runner: macos-11
+          #   nametag: macos11-py39
+          #   cc_compiler: /usr/local/opt/llvm@14/bin/clang
+          #   cxx_compiler: /usr/local/opt/llvm@14/bin/clang++
+          #   cxx_std: 17
+          #   python_ver: "3.10"
+          #   aclang: 13
+          #   setenvs: export LLVMBREWVER="@14" DO_BREW_UPDATE=1
+          #                   OPENIMAGEIO_VERSION=release
+          #                   QT_BREW_VERSION="@5"
           - desc: MacOS-12
             runner: macos-12
             nametag: macos12-p310
diff --git a/src/liboslexec/oslexec_pvt.h b/src/liboslexec/oslexec_pvt.h
index 05ae2e999c..7403049625 100644
--- a/src/liboslexec/oslexec_pvt.h
+++ b/src/liboslexec/oslexec_pvt.h
@@ -1468,11 +1468,13 @@ class ShaderInstance {
     /// instance overrides from the master copy.
     struct SymOverrideInfo {
         // Using bit fields to keep the data in 8 bytes in total.
-        unsigned char m_valuesource : 3;
-        bool m_connected_down : 1;
-        bool m_interpolated : 1;
-        bool m_interactive : 1;
-        int m_arraylen : 26;
+        // Note: it's important that all the bitfields are the same type
+        // (unsigned int), or MSVS won't merge them properly into one int.
+        unsigned int m_valuesource : 3;
+        unsigned int m_connected_down : 1;
+        unsigned int m_interpolated : 1;
+        unsigned int m_interactive : 1;
+        unsigned int m_arraylen : 26;
         int m_data_offset;
 
         SymOverrideInfo()