diff --git a/GarConvert.cs b/GarConvert.cs
index b0f57ef6..2c076c8a 100644
--- a/GarConvert.cs
+++ b/GarConvert.cs
@@ -173,7 +173,7 @@ namespace GARbro.GUI
                     if (source_ext == source_format)
                         return;
                     string output_name = Path.ChangeExtension (filename, source_format);
-                    using (var output = File.Create (output_name))
+                    using (var output = CreateNewFile (output_name))
                     {
                         input.Source.Position = 0;
                         input.Source.CopyTo (output);
@@ -184,7 +184,7 @@ namespace GARbro.GUI
                     if (source_ext == "wav")
                         return;
                     string output_name = Path.ChangeExtension (filename, "wav");
-                    using (var output = File.Create (output_name))
+                    using (var output = CreateNewFile (output_name))
                         WavFormat.Write (input, output);
                 }
             }
@@ -204,7 +204,7 @@ namespace GARbro.GUI
                     return;
                 try
                 {
-                    using (var output = File.Create (target_name))
+                    using (var output = CreateNewFile (target_name))
                         m_image_format.Write (output, image);
                 }
                 catch // delete destination file on conversion failure
@@ -215,6 +215,31 @@ namespace GARbro.GUI
             }
         }
 
+        /// <summary>
+        /// Creates new file with specified filename, or, if it's already exists, tries to open
+        /// files named "FILENAME.1.EXT", "FILENAME.2.EXT" and so on.
+        /// <exception cref="System.IOException">Throws exception after 100th failed attempt.</exception>
+        /// </summary>
+
+        public static Stream CreateNewFile (string filename)
+        {
+            string name = filename;
+            var ext = new Lazy<string> (() => Path.GetExtension (filename));
+            for (int attempt = 1; ; ++attempt)
+            {
+                try
+                {
+                    return File.Open (name, FileMode.CreateNew);
+                }
+                catch (IOException) // file already exists
+                {
+                    if (100 == attempt) // limit number of attempts
+                        throw;
+                }
+                name = Path.ChangeExtension (filename, attempt.ToString()+ext.Value);
+            }
+        }
+
         void OnConvertComplete (object sender, RunWorkerCompletedEventArgs e)
         {
             m_main.ResumeWatchDirectoryChanges();
diff --git a/GarExtract.cs b/GarExtract.cs
index a2a44436..5365d085 100644
--- a/GarExtract.cs
+++ b/GarExtract.cs
@@ -305,7 +305,7 @@ namespace GARbro.GUI
                     throw new InvalidFormatException (string.Format ("{1}: {0}", guiStrings.MsgUnableInterpretImage, entry.Name));
                 file.Position = 0;
                 string target_ext = target_format.Extensions.First();
-                string outname = Path.ChangeExtension (entry.Name, target_ext);
+                string outname = FindUniqueFileName (entry.Name, target_ext);
                 if (src_format.Item1 == target_format)
                 {
                     // source format is the same as a target, copy file as is
@@ -371,7 +371,7 @@ namespace GARbro.GUI
             string source_format = input.SourceFormat;
             if (GarConvertMedia.CommonAudioFormats.Contains (source_format))
             {
-                string output_name = Path.ChangeExtension (entry_name, source_format);
+                string output_name = FindUniqueFileName (entry_name, source_format);
                 using (var output = ArchiveFormat.CreateFile (output_name))
                 {
                     input.Source.Position = 0;
@@ -380,12 +380,25 @@ namespace GARbro.GUI
             }
             else
             {
-                string output_name = Path.ChangeExtension (entry_name, "wav");
+                string output_name = FindUniqueFileName (entry_name, "wav");
                 using (var output = ArchiveFormat.CreateFile (output_name))
                     GarConvertMedia.WavFormat.Write (input, output);
             }
         }
 
+        public static string FindUniqueFileName (string source_filename, string target_ext)
+        {
+            string ext = target_ext;
+            for (int attempt = 1; attempt < 100; ++attempt)
+            {
+                string filename = Path.ChangeExtension (source_filename, ext);
+                if (!File.Exists (filename))
+                    return filename;
+                ext = string.Format ("{0}.{1}", attempt, target_ext);
+            }
+            throw new IOException ("File aready exists");
+        }
+
         void OnExtractComplete (object sender, RunWorkerCompletedEventArgs e)
         {
             m_extract_in_progress = false;