diff --git a/eng/pipelines/runtime-diagnostics.yml b/eng/pipelines/runtime-diagnostics.yml
index 7adc3792d1375f..3c47d4522dfa92 100644
--- a/eng/pipelines/runtime-diagnostics.yml
+++ b/eng/pipelines/runtime-diagnostics.yml
@@ -15,11 +15,8 @@ parameters:
     - windows_arm64
     - linux_arm64
     - linux_arm
-    # TODO: Re-enable osx once disk space issue is resolved.
-    # macOS full dumps are ~5.7GB each; with 8+ full-dump debuggees the Helix
-    # machines run out of disk space (~45GB total). See PR #124782 for details.
-    # - osx_arm64
-    # - osx_x64
+    - osx_arm64
+    - osx_x64
 - name: cdacDumpTestMode
   displayName: cDAC Dump Test Mode
   type: string
diff --git a/src/native/managed/cdac/tests/DumpTests/cdac-dump-helix.proj b/src/native/managed/cdac/tests/DumpTests/cdac-dump-helix.proj
index cfa86393468487..a1e9d7206db94d 100644
--- a/src/native/managed/cdac/tests/DumpTests/cdac-dump-helix.proj
+++ b/src/native/managed/cdac/tests/DumpTests/cdac-dump-helix.proj
@@ -127,6 +127,10 @@
     <HelixPreCommand Include="set DOTNET_DbgEnableMiniDump=1" />
   </ItemGroup>
   <ItemGroup Condition="'$(TargetOS)' != 'windows'">
+    <!-- Check available disk space before running tests -->
+    <HelixPreCommand Include="df -h" />
+    <!-- Disable core dumps (ulimit -c 0) since system cores are too large and we create many intentional crashes for tests, which would fill the machine. -->
+    <HelixPreCommand Include="ulimit -c 0" />
     <HelixPreCommand Include="export DOTNET_DbgEnableMiniDump=1" />
     <HelixPreCommand Include="chmod +x $HELIX_CORRELATION_PAYLOAD/dotnet" />
   </ItemGroup>
diff --git a/src/native/managed/cdac/tests/DumpTests/cdac-dump-xplat-test-helix.proj b/src/native/managed/cdac/tests/DumpTests/cdac-dump-xplat-test-helix.proj
index d518c3ba23c16a..a8e869fca5bde3 100644
--- a/src/native/managed/cdac/tests/DumpTests/cdac-dump-xplat-test-helix.proj
+++ b/src/native/managed/cdac/tests/DumpTests/cdac-dump-xplat-test-helix.proj
@@ -69,6 +69,10 @@
 
   <!-- Pre-commands -->
   <ItemGroup Condition="'$(TargetOS)' != 'windows'">
+    <!-- Check available disk space before running tests -->
+    <HelixPreCommand Include="df -h" />
+    <!-- Disable core dumps (ulimit -c 0) since system cores are too large and we create many intentional crashes for tests, which would fill the machine. -->
+    <HelixPreCommand Include="ulimit -c 0" />
     <HelixPreCommand Include="chmod +x $HELIX_CORRELATION_PAYLOAD/dotnet" />
   </ItemGroup>