diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/dictionary_structure_with_buffer_policy_factory.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/dictionary_structure_with_buffer_policy_factory.cpp
index c81c61d23..04f119803 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/dictionary_structure_with_buffer_policy_factory.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/dictionary_structure_with_buffer_policy_factory.cpp
@@ -76,7 +76,7 @@ namespace latinime {
             }
             const Ver4DictBuffers::Ver4DictBuffersPtr dictBuffers =
                     Ver4DictBuffers::openVer4DictBuffers(dictPath, mmappedBuffer);
-            if (!dictBuffers.get()->isValid()) {
+            if (!dictBuffers.get() || !dictBuffers.get()->isValid()) {
                 AKLOGE("DICT: The dictionary doesn't satisfy ver4 format requirements. path: %s",
                         path);
                 ASSERT(false);
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.cpp
index 918c02ba2..59dedee72 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.cpp
@@ -28,9 +28,14 @@ namespace latinime {
 
 /* static */ Ver4DictBuffers::Ver4DictBuffersPtr Ver4DictBuffers::openVer4DictBuffers(
         const char *const dictPath, const MmappedBuffer::MmappedBufferPtr &headerBuffer) {
-    const bool isUpdatable = headerBuffer.get() ? headerBuffer.get()->isUpdatable() : false;
+    if (!headerBuffer.get()) {
+        ASSERT(false);
+        AKLOGE("The header buffer must be valid to open ver4 dict buffers.");
+        return Ver4DictBuffersPtr(0);
+    }
     // TODO: take only dictDirPath, and open both header and trie files in the constructor below
-    return Ver4DictBuffersPtr(new Ver4DictBuffers(dictPath, headerBuffer, isUpdatable));
+    return Ver4DictBuffersPtr(new Ver4DictBuffers(
+            dictPath, headerBuffer, headerBuffer.get()->isUpdatable()));
 }
 
 bool Ver4DictBuffers::flushHeaderAndDictBuffers(const char *const dictDirPath,
@@ -113,10 +118,11 @@ Ver4DictBuffers::Ver4DictBuffers(const char *const dictPath,
           mDictBuffer(MmappedBuffer::openBuffer(dictPath,
                   Ver4DictConstants::TRIE_FILE_EXTENSION, isUpdatable)),
           mHeaderPolicy(headerBuffer.get()->getBuffer(), FormatUtils::VERSION_4),
-          mExpandableHeaderBuffer(headerBuffer.get()->getBuffer(), mHeaderPolicy.getSize(),
+          mExpandableHeaderBuffer(headerBuffer.get() ? headerBuffer.get()->getBuffer() : 0,
+                  mHeaderPolicy.getSize(),
                   BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE),
-          mExpandableTrieBuffer(mDictBuffer.get()->getBuffer(),
-                  mDictBuffer.get()->getBufferSize(),
+          mExpandableTrieBuffer(mDictBuffer.get() ? mDictBuffer.get()->getBuffer() : 0,
+                  mDictBuffer.get() ? mDictBuffer.get()->getBufferSize() : 0,
                   BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE),
           mTerminalPositionLookupTable(dictPath, isUpdatable),
           mProbabilityDictContent(dictPath, mHeaderPolicy.hasHistoricalInfoOfWords(),
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.h b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.h
index a0c219e4d..776bb9882 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.h
@@ -42,7 +42,7 @@ class Ver4DictBuffers {
     }
 
     AK_FORCE_INLINE bool isValid() const {
-        return mDictBuffer.get() != 0 && mHeaderPolicy.isValid()
+        return mHeaderBuffer.get() && mDictBuffer.get() && mHeaderPolicy.isValid()
                 && mProbabilityDictContent.isValid() && mTerminalPositionLookupTable.isValid()
                 && mBigramDictContent.isValid() && mShortcutDictContent.isValid();
     }