diff --git a/compat/mac/AvailabilityVersions.h b/compat/mac/AvailabilityVersions.h
index 0bedb3d2..b9bb74ec 100644
--- a/compat/mac/AvailabilityVersions.h
+++ b/compat/mac/AvailabilityVersions.h
@@ -87,4 +87,10 @@
 #define __MAC_11_0 110000
 #endif
 
+// 12.0 SDK
+
+#ifndef __MAC_12_0
+#define __MAC_12_0 120000
+#endif
+
 #endif  // CRASHPAD_COMPAT_MAC_AVAILABILITYVERSIONS_H_
diff --git a/snapshot/mac/process_types/custom.cc b/snapshot/mac/process_types/custom.cc
index d80a984b..06c13001 100644
--- a/snapshot/mac/process_types/custom.cc
+++ b/snapshot/mac/process_types/custom.cc
@@ -147,6 +147,7 @@ size_t dyld_all_image_infos<Traits>::ExpectedSizeForVersion(
       std::numeric_limits<size_t>::max(),  // 15, see below
       offsetof(dyld_all_image_infos<Traits>, end_v16),  // 16
       sizeof(dyld_all_image_infos<Traits>),  // 17
+      sizeof(dyld_all_image_infos<Traits>),  // 18
   };
 
   if (version >= base::size(kSizeForVersion)) {
diff --git a/snapshot/mac/process_types/dyld_images.proctype b/snapshot/mac/process_types/dyld_images.proctype
index 589ad097..5c57a26f 100644
--- a/snapshot/mac/process_types/dyld_images.proctype
+++ b/snapshot/mac/process_types/dyld_images.proctype
@@ -127,12 +127,16 @@ PROCESS_TYPE_STRUCT_BEGIN(dyld_all_image_infos)
   // preceding the padding in the 32-bit structure that would natively be
   // addressed at index 4 of |reserved|. Treat reserved_4_32 as only available
   // in version 16 of the structure.
+  // In the 12.0 SDK, 2 of the trailing UIntPtrs on 64-bit and
+  // 4 of them on 32-bit were replaced by two uint64_ts. On 32-bit, that
+  // awkwardly straddles end_v14. Since macOS 12.0 is 64-bit only, the proctype
+  // version of this struct only has these uint64_ts in the 64-bit version.
   PROCESS_TYPE_STRUCT_MEMBER(UIntPtr, reserved, [4])
   PROCESS_TYPE_STRUCT_MEMBER(Reserved64_64Only, reserved_4_64)
   PROCESS_TYPE_STRUCT_MEMBER(Reserved64_64Only, reserved_5)
   PROCESS_TYPE_STRUCT_MEMBER(Reserved64_64Only, reserved_6)
-  PROCESS_TYPE_STRUCT_MEMBER(Reserved64_64Only, reserved_7)
-  PROCESS_TYPE_STRUCT_MEMBER(Reserved64_64Only, reserved_8)
+  PROCESS_TYPE_STRUCT_MEMBER(Reserved64_64Only, shared_cache_fs_id)
+  PROCESS_TYPE_STRUCT_MEMBER(Reserved64_64Only, shared_cache_fs_obj_id)
   PROCESS_TYPE_STRUCT_MEMBER(Nothing, end_v14)
   PROCESS_TYPE_STRUCT_MEMBER(Reserved32_32Only, reserved_4_32)
 
diff --git a/snapshot/mac/process_types_test.cc b/snapshot/mac/process_types_test.cc
index e0c3c9cb..90f5c1f6 100644
--- a/snapshot/mac/process_types_test.cc
+++ b/snapshot/mac/process_types_test.cc
@@ -356,8 +356,16 @@ TEST(ProcessTypes, DyldImagesSelf) {
               self_image_infos->reserved[4]);
     EXPECT_EQ(proctype_image_infos.reserved_5, self_image_infos->reserved[5]);
     EXPECT_EQ(proctype_image_infos.reserved_6, self_image_infos->reserved[6]);
-    EXPECT_EQ(proctype_image_infos.reserved_7, self_image_infos->reserved[7]);
-    EXPECT_EQ(proctype_image_infos.reserved_8, self_image_infos->reserved[8]);
+#if __MAC_OS_X_VERSION_MAX_ALLOWED >= __MAC_12_0
+    uint64_t shared_cache_fs_id = self_image_infos->sharedCacheFSID;
+    uint64_t shared_cache_fs_obj_id = self_image_infos->sharedCacheFSObjID;
+#else
+    uint64_t shared_cache_fs_id = self_image_infos->reserved[7];
+    uint64_t shared_cache_fs_obj_id = self_image_infos->reserved[8];
+#endif
+    EXPECT_EQ(proctype_image_infos.shared_cache_fs_id, shared_cache_fs_id);
+    EXPECT_EQ(proctype_image_infos.shared_cache_fs_obj_id,
+              shared_cache_fs_obj_id);
 #endif
   }
 #endif