diff --git a/internal/core/src/index/VectorDiskIndex.cpp b/internal/core/src/index/VectorDiskIndex.cpp
index f55b62b498..3f5cfc2b79 100644
--- a/internal/core/src/index/VectorDiskIndex.cpp
+++ b/internal/core/src/index/VectorDiskIndex.cpp
@@ -52,7 +52,8 @@ VectorDiskAnnIndex<T>::Load(const BinarySet& binary_set /* not used */, const Co
     auto index_files = GetValueFromConfig<std::vector<std::string>>(config, "index_files");
     AssertInfo(index_files.has_value(), "index file paths is empty when load disk ann index data");
     file_manager_->CacheIndexToDisk(index_files.value());
-    index_->Prepare(cfg);
+    auto ok = index_->Prepare(cfg);
+    AssertInfo(ok, "load disk index failed");
     SetDim(index_->Dim());
 }
 
diff --git a/internal/core/src/storage/DiskFileManagerImpl.cpp b/internal/core/src/storage/DiskFileManagerImpl.cpp
index befd499253..9be934b3c8 100644
--- a/internal/core/src/storage/DiskFileManagerImpl.cpp
+++ b/internal/core/src/storage/DiskFileManagerImpl.cpp
@@ -93,7 +93,7 @@ DiskFileManagerImpl::AddFile(const std::string& file) noexcept {
     // Split local data to multi part with specified size
     int slice_num = 0;
     auto remotePrefix = GetRemoteIndexObjectPrefix();
-    for (int offset = 0; offset < fileSize; slice_num++) {
+    for (int64_t offset = 0; offset < fileSize; slice_num++) {
         auto batch_size = std::min(milvus::config::KnowhereGetIndexSliceSize() << 20, int64_t(fileSize) - offset);
 
         auto fieldData = std::make_shared<FieldData>(buf.get() + offset, batch_size);