diff --git a/src/test/java/net/openhft/chronicle/map/ForEachSeqmentTest.java b/src/test/java/net/openhft/chronicle/map/ForEachSeqmentTest.java
new file mode 100644
index 000000000..4a334f3d7
--- /dev/null
+++ b/src/test/java/net/openhft/chronicle/map/ForEachSeqmentTest.java
@@ -0,0 +1,125 @@
+package net.openhft.chronicle.map;
+
+import net.openhft.chronicle.bytes.Bytes;
+import net.openhft.chronicle.core.Jvm;
+import net.openhft.chronicle.core.OS;
+import net.openhft.chronicle.core.pool.ClassAliasPool;
+import net.openhft.chronicle.hash.serialization.SizedReader;
+import net.openhft.chronicle.hash.serialization.SizedWriter;
+import net.openhft.chronicle.wire.AbstractBytesMarshallable;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.junit.Test;
+
+import java.io.File;
+import java.io.IOException;
+
+public class ForEachSeqmentTest {
+    static {
+        ClassAliasPool.CLASS_ALIASES.addAlias(MyDto.class);
+    }
+
+    @Test
+    public void forEachSegmentEntryWhileReleasesLock() throws IOException {
+        ChronicleMapBuilder<Integer, MyDto> builder = ChronicleMapBuilder.of(Integer.class, MyDto.class)
+                .entries(256)
+                .averageValueSize(128)
+                .actualSegments(1)
+                .valueMarshaller(new MyDtoMarshaller());
+        File tmp = new File(OS.TMP, "stressTest-" + System.nanoTime());
+        tmp.deleteOnExit();
+        try (ChronicleMap<Integer, MyDto> map = builder.createOrRecoverPersistedTo(tmp)) {
+            map.put(1, new MyDto());
+            try (MapSegmentContext<Integer, MyDto, ?> context = map.segmentContext(0)) {
+                context.forEachSegmentEntryWhile(e -> {
+                    System.out.println(e.key().get() + " = " + e.value().get());
+                    return true;
+                });
+            }
+            System.out.println("Done");
+        }
+    }
+
+    @Test
+    public void stressTest() throws IOException, InterruptedException {
+        ChronicleMapBuilder<Integer, MyDto> builder = ChronicleMapBuilder.of(Integer.class, MyDto.class)
+                .entries(256)
+                .averageValueSize(128)
+                .actualSegments(1)
+                .valueMarshaller(new MyDtoMarshaller());
+        File tmp = new File(OS.TMP, "stressTest-" + System.nanoTime());
+        Thread t = null;
+        try (ChronicleMap<Integer, MyDto> map = builder.createOrRecoverPersistedTo(tmp)) {
+            try {
+                t = new Thread(() -> {
+                    try {
+                        for (int i = 0; i < 100; i++) {
+                            System.out.println("put " + i);
+                            map.put(i, new MyDto());
+                            Thread.sleep(10);
+                        }
+                    } catch (InterruptedException e) {
+                        System.out.println("Interrupted");
+                    }
+                });
+                t.setDaemon(true);
+                t.start();
+                Jvm.pause(100);
+                try (MapSegmentContext<Integer, MyDto, ?> context = map.segmentContext(0)) {
+                    context.forEachSegmentEntryWhile(e -> {
+                        System.out.println(e.key().get() + " = " + e.value().get());
+                        Jvm.pause(10);
+                        return true;
+                    });
+                }
+                System.out.println("Done");
+                Jvm.pause(100);
+            } catch (Throwable th) {
+                th.printStackTrace();
+            } finally {
+                if (t != null) {
+                    t.interrupt();
+                    t.join();
+                }
+            }
+        }
+    }
+
+    static class MyDto extends AbstractBytesMarshallable {
+        String s1;
+        String s2;
+
+        public MyDto() {
+        }
+
+        public MyDto(final String s1, final String s2) {
+            this.s1 = s1;
+            this.s2 = s2;
+        }
+    }
+
+    static class MyDtoMarshaller implements SizedReader<MyDto>, SizedWriter<MyDto> {
+        transient Bytes bytes = Bytes.elasticByteBuffer();
+
+        @NotNull
+        @Override
+        public MyDto read(final Bytes in, final long size, @Nullable final MyDto using) {
+            MyDto u = using == null ? new MyDto() : using;
+            u.readMarshallable(in);
+            return u;
+        }
+
+        @Override
+        public long size(@NotNull final MyDto toWrite) {
+            bytes.clear();
+            write(bytes, 0, toWrite);
+            return bytes.readRemaining();
+        }
+
+        @Override
+        public void write(final Bytes out, final long size, @NotNull final MyDto toWrite) {
+            toWrite.writeMarshallable(out);
+        }
+    }
+
+}