diff --git a/reader/HDF5ImageSource.cpp b/reader/HDF5ImageSource.cpp
index 6022ed90..c207ccfa 100644
--- a/reader/HDF5ImageSource.cpp
+++ b/reader/HDF5ImageSource.cpp
@@ -116,7 +116,7 @@ HDF5ImageSource::GetDataset(const HDF5ImageLocator::Location &loc) const {
         entry.algorithm = dcpl.GetCompression();
 
     if (entry.direct_chunk && !loc.path.empty()) {
-        entry.raw = std::make_unique<RawFile>(loc.path);
+        entry.raw = std::make_shared<RawFile>(loc.path);
         if (!entry.raw->IsOpen())
             entry.raw.reset();
         hid_t fcpl = H5Fget_create_plist(loc.file->GetID());
@@ -148,7 +148,7 @@ HDF5ImageSource::PrepareDirectRead(const HDF5ImageLocator::Location &loc) const
     if (address == HADDR_UNDEF || size == 0)
         return {};
 
-    return DirectChunk{ds.raw.get(), ds.user_block + address, static_cast<uint32_t>(size),
+    return DirectChunk{ds.raw, ds.user_block + address, static_cast<uint32_t>(size),
                        ds.width, ds.height, ds.mode, ds.algorithm};
 }
 
diff --git a/reader/HDF5ImageSource.h b/reader/HDF5ImageSource.h
index f2763152..97cdaf30 100644
--- a/reader/HDF5ImageSource.h
+++ b/reader/HDF5ImageSource.h
@@ -47,7 +47,10 @@ public:
     // Where the bytes of one image are, and what they decode to. Everything needed to read an image
     // without calling HDF5 again.
     struct DirectChunk {
-        const RawFile *file = nullptr;
+        // Shared, not borrowed: GetRawImage drops the HDF5 lock before reading through this, so a
+        // concurrent Clear() - which ReadFile() and Close() both do - would otherwise free the file
+        // and close its descriptor under the reader.
+        std::shared_ptr<const RawFile> file;
         uint64_t address = 0;
         uint32_t size = 0;
         hsize_t width = 0;
@@ -100,7 +103,7 @@ private:
     struct OpenDataset {
         std::shared_ptr<HDF5ReadOnlyFile> file;
         std::unique_ptr<HDF5DataSet> dataset;
-        std::unique_ptr<RawFile> raw;
+        std::shared_ptr<RawFile> raw;
         // HDF5 addresses count from the end of the user block, so they are file offsets only once
         // its size is added. Zero for everything this project writes, but not for every file.
         uint64_t user_block = 0;