diff --git a/src/main/java/net/openhft/chronicle/hash/ChronicleHash.java b/src/main/java/net/openhft/chronicle/hash/ChronicleHash.java
index 4ee1d92c1..b5a7a31fa 100644
--- a/src/main/java/net/openhft/chronicle/hash/ChronicleHash.java
+++ b/src/main/java/net/openhft/chronicle/hash/ChronicleHash.java
@@ -23,7 +23,6 @@ import net.openhft.chronicle.set.ChronicleSet;
 
 import java.io.Closeable;
 import java.io.File;
-import java.io.IOException;
 
 /**
  * This interface defines common {@link ChronicleMap} and {@link ChronicleSet}, related to off-heap
@@ -61,5 +60,5 @@ public interface ChronicleHash extends Closeable {
      * <i>any</i> exception, or even JVM crash. Shortly speaking, don't call use map closing.
      */
     @Override
-    void close() throws IOException;
+    void close();
 }
diff --git a/src/main/java/net/openhft/chronicle/map/AbstractChronicleMapBuilder.java b/src/main/java/net/openhft/chronicle/map/AbstractChronicleMapBuilder.java
index 432b64bfc..590ff2b9d 100644
--- a/src/main/java/net/openhft/chronicle/map/AbstractChronicleMapBuilder.java
+++ b/src/main/java/net/openhft/chronicle/map/AbstractChronicleMapBuilder.java
@@ -782,7 +782,7 @@ public abstract class AbstractChronicleMapBuilder<K, V,
     }
 
     @Override
-    public ChronicleMap<K, V> create() throws IOException {
+    public ChronicleMap<K, V> create() {
         // clone() to make this builder instance thread-safe, because createWithoutFile() method
         // computes some state based on configurations, but doesn't synchronize on configuration
         // changes.
@@ -856,12 +856,17 @@ public abstract class AbstractChronicleMapBuilder<K, V,
     }
 
     ChronicleMap<K, V> createWithoutFile(
-            SingleChronicleHashReplication singleHashReplication, ReplicationChannel channel) throws IOException {
-        VanillaChronicleMap<K, ?, ?, V, ?, ?> map = newMap(singleHashReplication, channel);
-        BytesStore bytesStore = new DirectStore(JDKObjectSerializer.INSTANCE,
-                map.sizeInBytes(), true);
-        map.createMappedStoreAndSegments(bytesStore);
-        return establishReplication(map, singleHashReplication, channel);
+            SingleChronicleHashReplication singleHashReplication, ReplicationChannel channel) {
+        try {
+            VanillaChronicleMap<K, ?, ?, V, ?, ?> map = newMap(singleHashReplication, channel);
+            BytesStore bytesStore = new DirectStore(JDKObjectSerializer.INSTANCE,
+                    map.sizeInBytes(), true);
+            map.createMappedStoreAndSegments(bytesStore);
+            return establishReplication(map, singleHashReplication, channel);
+        } catch (IOException e) {
+            // file-less version should never trigger an IOException.
+            throw new AssertionError(e);
+        }
     }
 
     ChronicleMap<K, V> createStatelessMap(StatelessMapConfig<K, V> statelessBuilder)
diff --git a/src/main/java/net/openhft/chronicle/set/SetFromMap.java b/src/main/java/net/openhft/chronicle/set/SetFromMap.java
index 639184432..6ca6b9f4e 100644
--- a/src/main/java/net/openhft/chronicle/set/SetFromMap.java
+++ b/src/main/java/net/openhft/chronicle/set/SetFromMap.java
@@ -123,7 +123,7 @@ class SetFromMap<E> extends AbstractSet<E>
     }
 
     @Override
-    public void close() throws IOException {
+    public void close() {
         m.close();
     }
 }
diff --git a/src/test/java/net/openhft/chronicle/map/GuavaTest.java b/src/test/java/net/openhft/chronicle/map/GuavaTest.java
index 4c096767d..e6f48ad95 100644
--- a/src/test/java/net/openhft/chronicle/map/GuavaTest.java
+++ b/src/test/java/net/openhft/chronicle/map/GuavaTest.java
@@ -27,7 +27,6 @@ import junit.framework.Test;
 import junit.framework.TestCase;
 import junit.framework.TestSuite;
 
-import java.io.IOException;
 import java.util.List;
 import java.util.Map;
 
@@ -106,22 +105,14 @@ public class GuavaTest extends TestCase {
 
         @Override
         Map<CharSequence, CharSequence> newMap() {
-            try {
-                return builder.create();
-            } catch (IOException e) {
-                throw new AssertionError(e);
-            }
+            return builder.create();
         }
     }
 
     static class HHMTestGenerator extends CHMTestGenerator {
         @Override
         Map<CharSequence, CharSequence> newMap() {
-            try {
-                return builder.create();
-            } catch (IOException e) {
-                throw new AssertionError(e);
-            }
+            return builder.create();
         }
     }
 }
diff --git a/src/test/java/net/openhft/chronicle/map/ReplicationCheckingMap.java b/src/test/java/net/openhft/chronicle/map/ReplicationCheckingMap.java
index ee72bda1f..1be6f380b 100644
--- a/src/test/java/net/openhft/chronicle/map/ReplicationCheckingMap.java
+++ b/src/test/java/net/openhft/chronicle/map/ReplicationCheckingMap.java
@@ -22,7 +22,6 @@ import org.jetbrains.annotations.NotNull;
 import org.junit.Assert;
 
 import java.io.File;
-import java.io.IOException;
 import java.util.Collection;
 import java.util.Map;
 import java.util.Set;
@@ -268,7 +267,7 @@ public class ReplicationCheckingMap<K, V> implements ChronicleMap<K, V> {
     }
 
     @Override
-    public void close() throws IOException {
+    public void close() {
         map1.close();
         map2.close();
     }
diff --git a/src/test/java/net/openhft/chronicle/map/jrs166/map/StatelessChronicleMapTest.java b/src/test/java/net/openhft/chronicle/map/jrs166/map/StatelessChronicleMapTest.java
index 51b9e8fa4..4a251f27a 100755
--- a/src/test/java/net/openhft/chronicle/map/jrs166/map/StatelessChronicleMapTest.java
+++ b/src/test/java/net/openhft/chronicle/map/jrs166/map/StatelessChronicleMapTest.java
@@ -68,7 +68,7 @@ public class StatelessChronicleMapTest extends JSR166TestCase {
         }
 
         @Override
-        public void close() throws IOException {
+        public void close() {
             for (Closeable c : closeables) {
                 try {
                     c.close();