diff --git a/.github/workflows/ResInsightMac.yml b/.github/workflows/ResInsightMac.yml
index 165dbb97e0..4a1f7b3c05 100644
--- a/.github/workflows/ResInsightMac.yml
+++ b/.github/workflows/ResInsightMac.yml
@@ -166,16 +166,17 @@ jobs:
 
       - name: Restore vcpkg cache
         id: vcpkg-cache
-        uses: CeetronSolutions/vcpkg-cache@copilot/optimize-cache-storage-structure
+        # Restore only; saved after a successful Configure so partial caches are never written.
+        uses: actions/cache/restore@v6
         with:
-          cache-key: ${{ runner.os }}-${{ matrix.arch }}-clang-${{ steps.vcpkg-sha.outputs.sha }}-${{ hashFiles('vcpkg.json', 'vcpkg-configuration.json') }}
-          prefix: vcpkg-clang/
+          path: ${{ github.workspace }}/.vcpkg-cache
+          key: vcpkg-${{ runner.os }}-${{ matrix.arch }}-clang-${{ steps.vcpkg-sha.outputs.sha }}-${{ hashFiles('vcpkg.json', 'vcpkg-configuration.json') }}
 
       - name: Configure
         shell: bash
         env:
           VCPKG_FEATURE_FLAGS: "binarycaching"
-          VCPKG_BINARY_SOURCES: "clear;files,${{ steps.vcpkg-cache.outputs.path }},readwrite"
+          VCPKG_BINARY_SOURCES: "clear;files,${{ github.workspace }}/.vcpkg-cache,readwrite"
         run: >
           cmake -S . -B cmakebuild
           -DVCPKG_TARGET_TRIPLET=${{ matrix.arch }}-osx-release
@@ -195,6 +196,13 @@ jobs:
           -DCMAKE_TOOLCHAIN_FILE=ThirdParty/vcpkg/scripts/buildsystems/vcpkg.cmake
           -G Ninja
 
+      - name: Save vcpkg cache
+        if: success() && steps.vcpkg-cache.outputs.cache-hit != 'true'
+        uses: actions/cache/save@v6
+        with:
+          path: ${{ github.workspace }}/.vcpkg-cache
+          key: ${{ steps.vcpkg-cache.outputs.cache-primary-key }}
+
       - name: Build
         run: |
           cmake --build cmakebuild --target install
diff --git a/.github/workflows/ResInsightWithCache.yml b/.github/workflows/ResInsightWithCache.yml
index ba78c05e94..7627fe44c8 100644
--- a/.github/workflows/ResInsightWithCache.yml
+++ b/.github/workflows/ResInsightWithCache.yml
@@ -258,11 +258,14 @@ jobs:
 
       - name: Restore vcpkg cache
         id: vcpkg-cache
-        uses: CeetronSolutions/vcpkg-cache@copilot/optimize-cache-storage-structure
+        # Restore only. The cache is saved by the "Save vcpkg cache" step after a
+        # successful Configure, so failed or cancelled jobs never write partial
+        # caches.
+        uses: actions/cache/restore@v6
         with:
-          cache-key: ${{ runner.os }}-${{ matrix.config.cxx }}-${{ steps.image-version.outputs.version }}-${{ steps.compiler-hash.outputs.hash }}-${{ matrix.config.vcpkg-triplet }}-${{ steps.vcpkg-sha.outputs.sha }}-${{ hashFiles('vcpkg.json', 'vcpkg-configuration.json') }}
-          prefix: vcpkg-${{ matrix.config.cxx}}/
-          
+          path: ${{ github.workspace }}/.vcpkg-cache
+          key: vcpkg-${{ runner.os }}-${{ matrix.config.cxx }}-${{ steps.image-version.outputs.version }}-${{ steps.compiler-hash.outputs.hash }}-${{ matrix.config.vcpkg-triplet }}-${{ steps.vcpkg-sha.outputs.sha }}-${{ hashFiles('vcpkg.json', 'vcpkg-configuration.json') }}
+
       - name: Print CMake version
         shell: bash
         run: |
@@ -278,7 +281,7 @@ jobs:
         shell: bash
         env:
           VCPKG_FEATURE_FLAGS: "binarycaching" # Possibly redundant, but explicitly sets the binary caching feature flag
-          VCPKG_BINARY_SOURCES: "clear;files,${{ steps.vcpkg-cache.outputs.path }},readwrite"
+          VCPKG_BINARY_SOURCES: "clear;files,${{ github.workspace }}/.vcpkg-cache,readwrite"
           CC: ${{ matrix.config.cc }}
           CXX: ${{ matrix.config.cxx }}
         run: >
@@ -299,6 +302,14 @@ jobs:
           -DCMAKE_TOOLCHAIN_FILE=ThirdParty/vcpkg/scripts/buildsystems/vcpkg.cmake
           -G Ninja
 
+      - name: Save vcpkg cache
+        # Only after a fully successful Configure (all ports built)
+        if: success() && steps.vcpkg-cache.outputs.cache-hit != 'true'
+        uses: actions/cache/save@v6
+        with:
+          path: ${{ github.workspace }}/.vcpkg-cache
+          key: ${{ steps.vcpkg-cache.outputs.cache-primary-key }}
+
       - name: Build
         run: |
           cmake --build cmakebuild --target install
diff --git a/.github/workflows/clang-tidy.yml b/.github/workflows/clang-tidy.yml
index 0b863613e2..5e85fd1fa9 100644
--- a/.github/workflows/clang-tidy.yml
+++ b/.github/workflows/clang-tidy.yml
@@ -48,15 +48,17 @@ jobs:
 
       - name: Restore vcpkg cache
         id: vcpkg-cache
-        uses: CeetronSolutions/vcpkg-cache@copilot/optimize-cache-storage-structure
+        # Restore only; saved after a successful configure so partial caches are never written.
+        uses: actions/cache/restore@v6
         with:
-          cache-key: ${{ runner.os }}-clang-tidy-19-${{ steps.vcpkg-sha.outputs.sha }}-${{ hashFiles('vcpkg.json', 'vcpkg-configuration.json') }}
+          path: ${{ github.workspace }}/.vcpkg-cache
+          key: vcpkg-${{ runner.os }}-clang-tidy-19-${{ steps.vcpkg-sha.outputs.sha }}-${{ hashFiles('vcpkg.json', 'vcpkg-configuration.json') }}
 
       - name: Create compile commands and run clang-tidy
         # https://clang.llvm.org/extra/doxygen/run-clang-tidy_8py_source.html
         env:
           VCPKG_FEATURE_FLAGS: "binarycaching" # Possibly redundant, but explicitly sets the binary caching feature flag
-          VCPKG_BINARY_SOURCES: "clear;files,${{ steps.vcpkg-cache.outputs.path }},readwrite"
+          VCPKG_BINARY_SOURCES: "clear;files,${{ github.workspace }}/.vcpkg-cache,readwrite"
         run: |
           mkdir build
           cd build
@@ -70,6 +72,12 @@ jobs:
             -DCMAKE_EXPORT_COMPILE_COMMANDS=ON \
             -DCMAKE_TOOLCHAIN_FILE=ThirdParty/vcpkg/scripts/buildsystems/vcpkg.cmake \
             ..
+      - name: Save vcpkg cache
+        if: success() && steps.vcpkg-cache.outputs.cache-hit != 'true'
+        uses: actions/cache/save@v6
+        with:
+          path: ${{ github.workspace }}/.vcpkg-cache
+          key: ${{ steps.vcpkg-cache.outputs.cache-primary-key }}
       - name: Run clang-tidy and apply fixes
         continue-on-error: true
         run: |
diff --git a/.github/workflows/clazy-report.yml b/.github/workflows/clazy-report.yml
index 4391af0973..1ebda20777 100644
--- a/.github/workflows/clazy-report.yml
+++ b/.github/workflows/clazy-report.yml
@@ -56,14 +56,16 @@ jobs:
 
       - name: Restore vcpkg cache
         id: vcpkg-cache
-        uses: CeetronSolutions/vcpkg-cache@copilot/optimize-cache-storage-structure
+        # Restore only; saved after a successful configure so partial caches are never written.
+        uses: actions/cache/restore@v6
         with:
-          cache-key: ${{ runner.os }}-clang-tidy-19-${{ steps.vcpkg-sha.outputs.sha }}-${{ hashFiles('vcpkg.json', 'vcpkg-configuration.json') }}
+          path: ${{ github.workspace }}/.vcpkg-cache
+          key: vcpkg-${{ runner.os }}-clang-tidy-19-${{ steps.vcpkg-sha.outputs.sha }}-${{ hashFiles('vcpkg.json', 'vcpkg-configuration.json') }}
 
       - name: Create compile commands
         env:
           VCPKG_FEATURE_FLAGS: "binarycaching" # Possibly redundant, but explicitly sets the binary caching feature flag
-          VCPKG_BINARY_SOURCES: "clear;files,${{ steps.vcpkg-cache.outputs.path }},readwrite"
+          VCPKG_BINARY_SOURCES: "clear;files,${{ github.workspace }}/.vcpkg-cache,readwrite"
         run: |
           mkdir build
           cd build
@@ -77,6 +79,12 @@ jobs:
             -DCMAKE_EXPORT_COMPILE_COMMANDS=ON \
             -DCMAKE_TOOLCHAIN_FILE=ThirdParty/vcpkg/scripts/buildsystems/vcpkg.cmake \
             ..
+      - name: Save vcpkg cache
+        if: success() && steps.vcpkg-cache.outputs.cache-hit != 'true'
+        uses: actions/cache/save@v6
+        with:
+          path: ${{ github.workspace }}/.vcpkg-cache
+          key: ${{ steps.vcpkg-cache.outputs.cache-primary-key }}
       - name: Run clazy (Qt checks, report only)
         continue-on-error: true
         run: |