diff --git a/include/microStore/FileStore.h b/include/microStore/FileStore.h
index c243e21..0a6429a 100644
--- a/include/microStore/FileStore.h
+++ b/include/microStore/FileStore.h
@@ -1433,6 +1433,11 @@ USTORE_LOG("[ustore] Moving temporary file to: %s\n", seg0);
 	bool compact()
 	{
 USTORE_LOG("[ustore] Compacting storage...\n");
+		// The active segment is one of the sources removed below. LittleFS
+		// and FatFS refuse to unlink a file that is still open (POSIX would
+		// allow it), so close it first. Both exit paths reopen a segment so
+		// the store stays writable for callers that invoke compact() directly.
+		if (active_file) active_file.close();
 
 		// --- Phase 1: write COMPACTING journal (next_seg=0: no source segments deleted yet) ---
 		write_journal(JOURNAL_COMPACTING, 0, 0);
@@ -1542,6 +1547,7 @@ USTORE_LOG("[ustore] Closing tmp file: %s\n", tmp_path);
 		outf.close();
 
 		if (!write_ok) {
+			open_segment(current_segment);   // keep the store writable after a failed compaction
 			if (committed_segs == 0) {
 				// No source segments were deleted — safe to discard compact.tmp entirely.
 				USTORE_LOG("[ustore] WARNING: Compact aborted: storage full, all segments preserved\n");
@@ -1561,6 +1567,7 @@ USTORE_LOG("[ustore] Closing tmp file: %s\n", tmp_path);
 		write_journal(JOURNAL_COMMIT);
 
 		finalize_compaction();   // rename + index rebuild
+		open_segment(current_segment);   // seg0 = compacted data; internal callers move on to seg1
 
 		clear_journal();
 
diff --git a/test/test_file_store/test_file_store.cpp b/test/test_file_store/test_file_store.cpp
index 4f05dc7..13222d0 100644
--- a/test/test_file_store/test_file_store.cpp
+++ b/test/test_file_store/test_file_store.cpp
@@ -669,6 +669,39 @@ void test_file_store_compact_basic() {
     TEST_ASSERT_EQUAL(0, memcmp(buf, "v3", 2));
 }
 
+// A direct compact() call must leave the store writable. The active segment is
+// one of the source segments compaction deletes, so compact() has to close it
+// (LittleFS/FatFS refuse to unlink an open file) and reopen a segment before
+// returning; otherwise records written afterwards go to a stale handle and are
+// lost on reload.
+void test_file_store_compact_keeps_store_writable() {
+    reset_ram_fs();
+
+    uint32_t now = microStore::time();
+    {
+        microStore::FileStore store;
+        auto fs = make_ram_fs();
+        store.init(fs, "/p");
+        store.put("a", "v1", /*ttl=*/0, now);
+        store.put("b", "v2", /*ttl=*/0, now);
+        store.remove("b");
+        TEST_ASSERT_TRUE(store.compact());
+        store.put("c", "v3", /*ttl=*/0, now);   // written after compaction
+        TEST_ASSERT_TRUE(store.exists("c"));
+    }
+    remove_ram_file("/p_index.dat");   // force a rebuild from the segment files
+
+    microStore::FileStore reader;
+    auto fs = make_ram_fs();
+    reader.init(fs, "/p");
+
+    TEST_ASSERT_EQUAL(2u, reader.size());   // a(v1) and c(v3)
+    uint8_t buf[32]; uint16_t sz = sizeof(buf);
+    TEST_ASSERT_TRUE(reader.get("c", buf, &sz));
+    TEST_ASSERT_EQUAL(2u, sz);
+    TEST_ASSERT_EQUAL(0, memcmp(buf, "v3", 2));
+}
+
 /* ===========================================================================
  * Directory-mode prefix tests
  *
@@ -800,6 +833,7 @@ int runUnityTests(void) {
     // Additional edge-case tests
     RUN_TEST(test_file_store_ttl_exists_expires);
     RUN_TEST(test_file_store_compact_basic);
+    RUN_TEST(test_file_store_compact_keeps_store_writable);
     // Directory-mode prefix
     RUN_TEST(test_dir_prefix_segment_and_index_names);
     RUN_TEST(test_legacy_prefix_unchanged);