diff --git a/Collection.go b/Collection.go
index 43de64b..42b7076 100644
--- a/Collection.go
+++ b/Collection.go
@@ -5,6 +5,7 @@ import (
 	"os"
 	"path/filepath"
 	"reflect"
+	"strings"
 	"sync"
 )
 
@@ -133,18 +134,19 @@ func (c *collection[T]) Clear() {
 
 // keyFile returns the file path for the given key.
 func (c *collection[T]) keyFile(key string) string {
-	return filepath.Join(c.directory, key)
+	return filepath.Join(c.directory, key+".json")
 }
 
 // loadFromDisk loads the collection data from the disk.
 func (c *collection[T]) loadFromDisk() error {
-	file, err := os.Open(c.directory)
+	dir, err := os.Open(c.directory)
 
 	if err != nil {
 		return err
 	}
 
-	files, err := file.Readdirnames(0)
+	defer dir.Close()
+	files, err := dir.Readdirnames(0)
 
 	for _, key := range files {
 		fileError := c.loadFileFromDisk(key)
@@ -154,16 +156,12 @@ func (c *collection[T]) loadFromDisk() error {
 		}
 	}
 
-	if err != nil {
-		return err
-	}
-
-	return file.Close()
+	return err
 }
 
 // loadFileFromDisk loads a single file from the disk.
-func (c *collection[T]) loadFileFromDisk(key string) error {
-	file, err := os.Open(filepath.Join(c.directory, key))
+func (c *collection[T]) loadFileFromDisk(fileName string) error {
+	file, err := os.Open(filepath.Join(c.directory, fileName))
 
 	if err != nil {
 		return err
@@ -178,6 +176,7 @@ func (c *collection[T]) loadFileFromDisk(key string) error {
 		return err
 	}
 
+	key := strings.TrimSuffix(fileName, ".json")
 	c.data.Store(key, value)
 	return file.Close()
 }
@@ -185,7 +184,7 @@ func (c *collection[T]) loadFileFromDisk(key string) error {
 // writeFileToDisk writes the value for the key to disk as a JSON file.
 func (c *collection[T]) writeFileToDisk(key string, value *T) error {
 	fileName := c.keyFile(key)
-	file, err := os.Create(fileName)
+	file, err := os.OpenFile(fileName, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0600)
 
 	if err != nil {
 		return err
diff --git a/Collection_test.go b/Collection_test.go
index 4474dd8..ecc8269 100644
--- a/Collection_test.go
+++ b/Collection_test.go
@@ -1,6 +1,8 @@
 package ocean_test
 
 import (
+	"fmt"
+	"strconv"
 	"sync"
 	"testing"
 
@@ -196,3 +198,24 @@ func BenchmarkDelete(b *testing.B) {
 
 	b.StopTimer()
 }
+
+func BenchmarkColdStart100Files(b *testing.B) {
+	users, err := ocean.New[User]("test")
+	assert.Nil(b, err)
+	defer users.Clear()
+
+	for i := 0; i < 100; i++ {
+		users.Set(strconv.Itoa(i), &User{Name: fmt.Sprintf("User %d", i)})
+	}
+
+	b.ReportAllocs()
+	b.ResetTimer()
+
+	for n := 0; n < b.N; n++ {
+		again, err := ocean.New[User]("test")
+		assert.Nil(b, err)
+		assert.NotNil(b, again)
+	}
+
+	b.StopTimer()
+}