diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 27d0ce7..09443e7 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -30,12 +30,15 @@ jobs:
         # under C++ 20 seems to be 1.75. That was released 2020-12-11, over three years
         # ago so I'm comfortable calling that "oldest", now. Let's call 1.81 (one year ago)
         # "pinned".
-        boost: [oldest, pinned, latest]
+        # Coming back to this 2024-10-09, I can no longer get 1.75 to build on MacOS--
+        # removing it for now.
+        # boost: [oldest, pinned, latest]
+        boost: [pinned, latest]
         include:
-        - os: macos-14
-          boost: oldest
-          boost-ver: 1_75_0
-          boost-dl: https://boostorg.jfrog.io/artifactory/main/release/1.75.0/source/boost_1_75_0.tar.bz2
+        # - os: macos-14
+        #   boost: oldest
+        #   boost-ver: 1_75_0
+        #   boost-dl: https://boostorg.jfrog.io/artifactory/main/release/1.75.0/source/boost_1_75_0.tar.bz2
         - os: macos-14
           boost: pinned
           boost-ver: 1_81_0
@@ -44,10 +47,10 @@ jobs:
           boost: latest
           boost-ver: 1_84_0
           boost-dl: https://boostorg.jfrog.io/artifactory/main/release/1.84.0/source/boost_1_84_0.tar.bz2
-        - os: ubuntu-22.04
-          boost: oldest
-          boost-ver: 1_75_0
-          boost-dl: https://boostorg.jfrog.io/artifactory/main/release/1.75.0/source/boost_1_75_0.tar.bz2
+        # - os: ubuntu-22.04
+        #   boost: oldest
+        #   boost-ver: 1_75_0
+        #   boost-dl: https://boostorg.jfrog.io/artifactory/main/release/1.75.0/source/boost_1_75_0.tar.bz2
         - os: ubuntu-22.04
           boost: pinned
           boost-ver: 1_81_0