diff --git a/src/flatfile.cpp b/src/flatfile.cpp
index 388b30efae..df6596e940 100644
--- a/src/flatfile.cpp
+++ b/src/flatfile.cpp
@@ -46,7 +46,9 @@ FILE* FlatFileSeq::Open(const FlatFilePos& pos, bool read_only) const
     }
     if (pos.nPos && fseek(file, pos.nPos, SEEK_SET)) {
         LogPrintf("Unable to seek to position %u of %s\n", pos.nPos, fs::PathToString(path));
-        fclose(file);
+        if (fclose(file) != 0) {
+            LogError("Unable to close file %s", fs::PathToString(path));
+        }
         return nullptr;
     }
     return file;
@@ -68,7 +70,10 @@ size_t FlatFileSeq::Allocate(const FlatFilePos& pos, size_t add_size, bool& out_
             if (file) {
                 LogDebug(BCLog::VALIDATION, "Pre-allocating up to position 0x%x in %s%05u.dat\n", new_size, m_prefix, pos.nFile);
                 AllocateFileRange(file, pos.nPos, inc_size);
-                fclose(file);
+                if (fclose(file) != 0) {
+                    LogError("Cannot close file %s%05u.dat after extending it with %u bytes", m_prefix, pos.nFile, new_size);
+                    return 0;
+                }
                 return inc_size;
             }
         } else {
@@ -86,17 +91,24 @@ bool FlatFileSeq::Flush(const FlatFilePos& pos, bool finalize) const
         return false;
     }
     if (finalize && !TruncateFile(file, pos.nPos)) {
-        fclose(file);
         LogError("%s: failed to truncate file %d\n", __func__, pos.nFile);
+        if (fclose(file) != 0) {
+            LogError("Failed to close file %d", pos.nFile);
+        }
         return false;
     }
     if (!FileCommit(file)) {
-        fclose(file);
         LogError("%s: failed to commit file %d\n", __func__, pos.nFile);
+        if (fclose(file) != 0) {
+            LogError("Failed to close file %d", pos.nFile);
+        }
         return false;
     }
     DirectoryCommit(m_dir);
 
-    fclose(file);
+    if (fclose(file) != 0) {
+        LogError("Failed to close file %d after flush", pos.nFile);
+        return false;
+    }
     return true;
 }
diff --git a/src/node/blockstorage.cpp b/src/node/blockstorage.cpp
index 557ddaceab..81f42827d9 100644
--- a/src/node/blockstorage.cpp
+++ b/src/node/blockstorage.cpp
@@ -961,6 +961,7 @@ bool BlockManager::WriteBlockUndo(const CBlockUndo& blockundo, BlockValidationSt
                 // Write undo data & checksum
                 fileout << blockundo << hasher.GetHash();
             }
+            // BufferedWriter will flush pending data to file when fileout goes out of scope.
         }
 
         // Make sure that the file is closed before we call `FlushUndoFile`.
diff --git a/src/node/mempool_persist.cpp b/src/node/mempool_persist.cpp
index 2551a43166..d4d9263973 100644
--- a/src/node/mempool_persist.cpp
+++ b/src/node/mempool_persist.cpp
@@ -201,8 +201,10 @@ bool DumpMempool(const CTxMemPool& pool, const fs::path& dump_path, FopenFn mock
         LogInfo("Writing %d unbroadcast transactions to file.\n", unbroadcast_txids.size());
         file << unbroadcast_txids;
 
-        if (!skip_file_commit && !file.Commit())
+        if (!skip_file_commit && !file.Commit()) {
+            (void)file.fclose();
             throw std::runtime_error("Commit failed");
+        }
         if (file.fclose() != 0) {
             throw std::runtime_error(
                 strprintf("Error closing %s: %s", fs::PathToString(file_fspath), SysErrorString(errno)));
diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index 4f5a6b8434..be953cefde 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -83,7 +83,7 @@ UniValue WriteUTXOSnapshot(
     CCoinsViewCursor* pcursor,
     CCoinsStats* maybe_stats,
     const CBlockIndex* tip,
-    AutoFile& afile,
+    AutoFile&& afile,
     const fs::path& path,
     const fs::path& temppath,
     const std::function<void()>& interruption_point = {});
@@ -3115,7 +3115,14 @@ static RPCHelpMan dumptxoutset()
         }
     }
 
-    UniValue result = WriteUTXOSnapshot(*chainstate, cursor.get(), &stats, tip, afile, path, temppath, node.rpc_interruption_point);
+    UniValue result = WriteUTXOSnapshot(*chainstate,
+                                        cursor.get(),
+                                        &stats,
+                                        tip,
+                                        std::move(afile),
+                                        path,
+                                        temppath,
+                                        node.rpc_interruption_point);
     fs::rename(temppath, path);
 
     result.pushKV("path", path.utf8string());
@@ -3167,7 +3174,7 @@ UniValue WriteUTXOSnapshot(
     CCoinsViewCursor* pcursor,
     CCoinsStats* maybe_stats,
     const CBlockIndex* tip,
-    AutoFile& afile,
+    AutoFile&& afile,
     const fs::path& path,
     const fs::path& temppath,
     const std::function<void()>& interruption_point)
@@ -3244,12 +3251,19 @@ UniValue WriteUTXOSnapshot(
 UniValue CreateUTXOSnapshot(
     node::NodeContext& node,
     Chainstate& chainstate,
-    AutoFile& afile,
+    AutoFile&& afile,
     const fs::path& path,
     const fs::path& tmppath)
 {
     auto [cursor, stats, tip]{WITH_LOCK(::cs_main, return PrepareUTXOSnapshot(chainstate, node.rpc_interruption_point))};
-    return WriteUTXOSnapshot(chainstate, cursor.get(), &stats, tip, afile, path, tmppath, node.rpc_interruption_point);
+    return WriteUTXOSnapshot(chainstate,
+                             cursor.get(),
+                             &stats,
+                             tip,
+                             std::move(afile),
+                             path,
+                             tmppath,
+                             node.rpc_interruption_point);
 }
 
 static RPCHelpMan loadtxoutset()
diff --git a/src/rpc/blockchain.h b/src/rpc/blockchain.h
index b42fe96fd3..0e42bed947 100644
--- a/src/rpc/blockchain.h
+++ b/src/rpc/blockchain.h
@@ -51,7 +51,7 @@ void CalculatePercentilesByWeight(CAmount result[NUM_GETBLOCKSTATS_PERCENTILES],
 UniValue CreateUTXOSnapshot(
     node::NodeContext& node,
     Chainstate& chainstate,
-    AutoFile& afile,
+    AutoFile&& afile,
     const fs::path& path,
     const fs::path& tmppath);
 
diff --git a/src/streams.cpp b/src/streams.cpp
index 3c46530990..2c873e50d3 100644
--- a/src/streams.cpp
+++ b/src/streams.cpp
@@ -119,6 +119,7 @@ bool AutoFile::Commit()
 
 bool AutoFile::Truncate(unsigned size)
 {
+    m_was_written = true;
     return ::TruncateFile(m_file, size);
 }
 
diff --git a/src/test/util/chainstate.h b/src/test/util/chainstate.h
index eebf504d98..d5100d15b1 100644
--- a/src/test/util/chainstate.h
+++ b/src/test/util/chainstate.h
@@ -47,8 +47,11 @@ CreateAndActivateUTXOSnapshot(
     FILE* outfile{fsbridge::fopen(snapshot_path, "wb")};
     AutoFile auto_outfile{outfile};
 
-    UniValue result = CreateUTXOSnapshot(
-        node, node.chainman->ActiveChainstate(), auto_outfile, snapshot_path, snapshot_path); // Will close auto_outfile.
+    UniValue result = CreateUTXOSnapshot(node,
+                                         node.chainman->ActiveChainstate(),
+                                         std::move(auto_outfile), // Will close auto_outfile.
+                                         snapshot_path,
+                                         snapshot_path);
     LogPrintf(
         "Wrote UTXO snapshot to %s: %s\n", fs::PathToString(snapshot_path.make_preferred()), result.write());