diff --git a/src/api/burn/balutil/msg.cpp b/src/api/burn/balutil/msg.cpp
index bf2157813..e0eb03d2b 100644
--- a/src/api/burn/balutil/msg.cpp
+++ b/src/api/burn/balutil/msg.cpp
@@ -504,13 +504,16 @@ static HRESULT OnCacheAcquireResolving(
     hr = BuffReaderReadNumber(pReader, &cSearchPaths);
     ExitOnFailure(hr, "Failed to read overall percentage of OnCacheAcquireResolving args.");
 
-    rgsczSearchPaths = static_cast<LPWSTR*>(MemAlloc(sizeof(LPWSTR) * cSearchPaths, TRUE));
-    ExitOnNull(rgsczSearchPaths, hr, E_OUTOFMEMORY, "Failed to allocate memory for search paths.");
-
-    for (DWORD i = 0; i < cSearchPaths; ++i)
+    if (cSearchPaths)
     {
-        hr = BuffReaderReadString(pReader, &rgsczSearchPaths[i]);
-        ExitOnFailure(hr, "Failed to read search path[%u] of OnCacheAcquireResolving args.", i);
+        rgsczSearchPaths = static_cast<LPWSTR*>(MemAlloc(sizeof(LPWSTR) * cSearchPaths, TRUE));
+        ExitOnNull(rgsczSearchPaths, hr, E_OUTOFMEMORY, "Failed to allocate memory for search paths of OnCacheAcquireResolving args.");
+
+        for (DWORD i = 0; i < cSearchPaths; ++i)
+        {
+            hr = BuffReaderReadString(pReader, &rgsczSearchPaths[i]);
+            ExitOnFailure(hr, "Failed to read search path[%u] of OnCacheAcquireResolving args.", i);
+        }
     }
 
     args.cSearchPaths = cSearchPaths;
@@ -943,6 +946,9 @@ static HRESULT OnCachePackageComplete(
     hr = BuffReaderReadNumber(pReader, &results.cbSize);
     ExitOnFailure(hr, "Failed to read size of OnCachePackageComplete results.");
 
+    hr = BuffReaderReadNumber(pReader, reinterpret_cast<DWORD*>(&results.action));
+    ExitOnFailure(hr, "Failed to read action of OnCachePackageComplete results.");
+
     // Callback.
     hr = pApplication->BAProc(BOOTSTRAPPER_APPLICATION_MESSAGE_ONCACHEPACKAGECOMPLETE, &args, &results);
 
@@ -2669,13 +2675,16 @@ static HRESULT OnError(
     hr = BuffReaderReadNumber(pReader, &cData);
     ExitOnFailure(hr, "Failed to read count of data of OnError args.");
 
-    rgsczData = static_cast<LPWSTR*>(MemAlloc(sizeof(LPWSTR) * cData, TRUE));
-    ExitOnNull(rgsczData, hr, E_OUTOFMEMORY, "Failed to allocate memory for search paths.");
-
-    for (DWORD i = 0; i < cData; ++i)
+    if (cData)
     {
-        hr = BuffReaderReadString(pReader, &rgsczData[i]);
-        ExitOnFailure(hr, "Failed to read search path[%u] of OnCacheAcquireResolving args.", i);
+        rgsczData = static_cast<LPWSTR*>(MemAlloc(sizeof(LPWSTR) * cData, TRUE));
+        ExitOnNull(rgsczData, hr, E_OUTOFMEMORY, "Failed to allocate memory for data of OnError args.");
+
+        for (DWORD i = 0; i < cData; ++i)
+        {
+            hr = BuffReaderReadString(pReader, &rgsczData[i]);
+            ExitOnFailure(hr, "Failed to read search path[%u] of OnError args.", i);
+        }
     }
 
     args.cData = cData;
@@ -2839,13 +2848,16 @@ static HRESULT OnExecuteFilesInUse(
     hr = BuffReaderReadNumber(pReader, &cFiles);
     ExitOnFailure(hr, "Failed to read count of files of OnExecuteFilesInUse args.");
 
-    rgsczFiles = static_cast<LPWSTR*>(MemAlloc(sizeof(LPWSTR) * cFiles, TRUE));
-    ExitOnNull(rgsczFiles, hr, E_OUTOFMEMORY, "Failed to allocate memory for files in OnExecuteFilesInUse.");
-
-    for (DWORD i = 0; i < cFiles; ++i)
+    if (cFiles)
     {
-        hr = BuffReaderReadString(pReader, &rgsczFiles[i]);
-        ExitOnFailure(hr, "Failed to read file[%u] of OnExecuteFilesInUse args.", i);
+        rgsczFiles = static_cast<LPWSTR*>(MemAlloc(sizeof(LPWSTR) * cFiles, TRUE));
+        ExitOnNull(rgsczFiles, hr, E_OUTOFMEMORY, "Failed to allocate memory for files of OnExecuteFilesInUse args.");
+
+        for (DWORD i = 0; i < cFiles; ++i)
+        {
+            hr = BuffReaderReadString(pReader, &rgsczFiles[i]);
+            ExitOnFailure(hr, "Failed to read file[%u] of OnExecuteFilesInUse args.", i);
+        }
     }
 
     args.cFiles = cFiles;
@@ -2933,13 +2945,16 @@ static HRESULT OnExecuteMsiMessage(
     hr = BuffReaderReadNumber(pReader, &cData);
     ExitOnFailure(hr, "Failed to read count of files of OnExecuteMsiMessage args.");
 
-    rgsczData = static_cast<LPWSTR*>(MemAlloc(sizeof(LPWSTR) * cData, TRUE));
-    ExitOnNull(rgsczData, hr, E_OUTOFMEMORY, "Failed to allocate memory for files in OnExecuteMsiMessage.");
-
-    for (DWORD i = 0; i < cData; ++i)
+    if (cData)
     {
-        hr = BuffReaderReadString(pReader, &rgsczData[i]);
-        ExitOnFailure(hr, "Failed to read data[%u] of OnExecuteMsiMessage args.", i);
+        rgsczData = static_cast<LPWSTR*>(MemAlloc(sizeof(LPWSTR) * cData, TRUE));
+        ExitOnNull(rgsczData, hr, E_OUTOFMEMORY, "Failed to allocate memory for data of OnExecuteMsiMessage args.");
+
+        for (DWORD i = 0; i < cData; ++i)
+        {
+            hr = BuffReaderReadString(pReader, &rgsczData[i]);
+            ExitOnFailure(hr, "Failed to read data[%u] of OnExecuteMsiMessage args.", i);
+        }
     }
 
     args.cData = cData;
diff --git a/src/burn/engine/bacallback.cpp b/src/burn/engine/bacallback.cpp
index 679cc5acf..45a29ac90 100644
--- a/src/burn/engine/bacallback.cpp
+++ b/src/burn/engine/bacallback.cpp
@@ -1193,6 +1193,9 @@ EXTERN_C HRESULT BACallbackOnCachePackageComplete(
     hr = BuffWriteNumberToBuffer(&buffer, results.cbSize);
     ExitOnFailure(hr, "Failed to write size of OnCachePackageComplete results.");
 
+    hr = BuffWriteNumberToBuffer(&buffer, results.action);
+    ExitOnFailure(hr, "Failed to write action of OnCachePackageComplete results.");
+
     hr = BuffEnsurePaddingInBuffer(&buffer, args.cbSize + results.cbSize);
     ExitOnFailure(hr, "Failed to add padding to OnCachePackageComplete results.");