diff --git a/roaring/roaring.go b/roaring/roaring.go
index 464389de6..6dfd110ca 100644
--- a/roaring/roaring.go
+++ b/roaring/roaring.go
@@ -615,7 +615,7 @@ func (b *Bitmap) UnmarshalBinary(data []byte) error {
 		b.keys[i] = binary.LittleEndian.Uint64(buf[0:8])
 		b.containers[i] = &container{
 			container_type: byte(binary.LittleEndian.Uint16(buf[8:10])),
-			n:              int(binary.LittleEndian.Uint16(buf[10:12]) + 1),
+			n:              int(binary.LittleEndian.Uint16(buf[10:12])) + 1,
 			mapped:         true,
 		}
 	}
@@ -1236,7 +1236,6 @@ func (c *container) Optimize() {
 	}
 	runs := c.countRuns()
 
-	// First decide which type to use.
 	var newType byte
 	if runs <= RunMaxSize && runs <= c.n/2 {
 		newType = ContainerRun
@@ -1259,22 +1258,12 @@ func (c *container) Optimize() {
 		} else if newType == ContainerRun {
 			c.bitmapToRun()
 		}
-		e := c.check()
-		if e != nil {
-			fmt.Printf("Bitmap %v\n", c)
-			panic(e)
-		}
 	} else if c.isRun() {
 		if newType == ContainerBitmap {
 			c.runToBitmap()
 		} else if newType == ContainerArray {
 			c.runToArray()
 		}
-		e := c.check()
-		if e != nil {
-			fmt.Printf("Run %v\n", c)
-			panic(e)
-		}
 	}
 }
 
diff --git a/roaring/roaring_internal_test.go b/roaring/roaring_internal_test.go
index cf2c51205..89741b0e3 100644
--- a/roaring/roaring_internal_test.go
+++ b/roaring/roaring_internal_test.go
@@ -1634,6 +1634,35 @@ func TestWriteReadBitmap(t *testing.T) {
 	}
 }
 
+func TestWriteReadFullBitmap(t *testing.T) {
+	// create bitmap containing > 4096 bits
+	cb := &container{bitmap: make([]uint64, bitmapN), n: 65536, container_type: ContainerBitmap}
+	for i := 0; i < bitmapN; i++ {
+		cb.bitmap[i] = 0xffffffffffffffff
+	}
+	bb := &Bitmap{keys: []uint64{0}, containers: []*container{cb}}
+	bb2 := &Bitmap{}
+	var buf bytes.Buffer
+	_, err := bb.WriteTo(&buf)
+	if err != nil {
+		t.Fatalf("error writing: %v", err)
+	}
+	err = bb2.UnmarshalBinary(buf.Bytes())
+	if err != nil {
+		t.Fatalf("error unmarshaling: %v", err)
+	}
+	if !reflect.DeepEqual(bb2.containers[0].bitmap, cb.bitmap) {
+		t.Fatalf("bitmap test expected %x, but got %x", cb.bitmap, bb2.containers[0].bitmap)
+	}
+
+	if bb2.containers[0].n != cb.n {
+		t.Fatalf("bitmap test expected count %x, but got %x", cb.n, bb2.containers[0].n)
+	}
+	if bb2.containers[0].count() != cb.count() {
+		t.Fatalf("bitmap test expected count %x, but got %x", cb.n, bb2.containers[0].n)
+	}
+}
+
 func TestWriteReadRun(t *testing.T) {
 	cr := &container{runs: []interval16{{start: 3, last: 13}, {start: 100, last: 109}}, n: 21, container_type: ContainerRun}
 	br := &Bitmap{keys: []uint64{0}, containers: []*container{cr}}