diff --git a/ChangeLog b/ChangeLog
index eb759c5d2..66dedfe47 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2005-01-30  Moritz Bunkus  <moritz@bunkus.org>
+
+	* mmg: bug fix: Overwriting a chapter file did not erase the
+	previous file. So if the previous file was bigger than the current
+	chapters then garbage remained at the end of the file.
+
 2005-01-20  Moritz Bunkus  <moritz@bunkus.org>
 
 	* mmg: bug fix: The "stretch" input box tooltip was wrong. The
diff --git a/src/base64tool.cpp b/src/base64tool.cpp
index 9fbeebf70..70c4f9f26 100644
--- a/src/base64tool.cpp
+++ b/src/base64tool.cpp
@@ -82,7 +82,7 @@ main(int argc,
   }
 
   try {
-    out = new mm_file_io_c(argv[3], MODE_WRITE);
+    out = new mm_file_io_c(argv[3], MODE_CREATE);
   } catch(...) {
     mxerror(_("The file '%s' could not be opened for writing (%d, %s).\n"),
             argv[3], errno, strerror(errno));
diff --git a/src/common/mm_io.cpp b/src/common/mm_io.cpp
index 927720b79..169bcdb5f 100644
--- a/src/common/mm_io.cpp
+++ b/src/common/mm_io.cpp
@@ -44,13 +44,13 @@ mm_file_io_c::mm_file_io_c(const string &path,
       cmode = "rb";
       break;
     case MODE_WRITE:
-      cmode = "wb";
+      cmode = "a+b";
       break;
     case MODE_CREATE:
-      cmode = "wb+";
+      cmode = "w+b";
       break;
     case MODE_SAFE:
-      cmode = "r+b";
+      cmode = "rb";
       break;
     default:
       throw 0;
@@ -122,7 +122,7 @@ mm_file_io_c::truncate(int64_t pos) {
   return ftruncate(fileno((FILE *)file), pos);
 }
 
-#else // SYS_UNIX
+#else // SYS_WINDOWS
 
 HANDLE
 CreateFileUtf8(LPCSTR lpFileName,
diff --git a/src/extract/attachments.cpp b/src/extract/attachments.cpp
index e8751dca7..611827499 100644
--- a/src/extract/attachments.cpp
+++ b/src/extract/attachments.cpp
@@ -130,7 +130,7 @@ handle_attachments(KaxAttachments *atts) {
                  "is written to '%s'.\n"), id, type.c_str(), size,
                tracks[k].out_name);
         try {
-          out = new mm_file_io_c(tracks[k].out_name, MODE_WRITE);
+          out = new mm_file_io_c(tracks[k].out_name, MODE_CREATE);
         } catch (...) {
           mxerror(_("The file '%s' could not be opened for writing "
                     "(%d, %s).\n"),
diff --git a/src/extract/tracks.cpp b/src/extract/tracks.cpp
index f24898ea5..bafee50bd 100644
--- a/src/extract/tracks.cpp
+++ b/src/extract/tracks.cpp
@@ -1278,7 +1278,7 @@ write_all_cuesheets(KaxChapters &chapters,
       cue_file_name += ".cue";
 
       try {
-        out = new mm_file_io_c(cue_file_name.c_str(), MODE_WRITE);
+        out = new mm_file_io_c(cue_file_name.c_str(), MODE_CREATE);
       } catch(...) {
         mxerror(_("The file '%s' could not be opened for writing (%s).\n"),
                 cue_file_name.c_str(), strerror(errno));
diff --git a/src/mmg/tab_chapters.cpp b/src/mmg/tab_chapters.cpp
index da81ef91c..45e0b6210 100644
--- a/src/mmg/tab_chapters.cpp
+++ b/src/mmg/tab_chapters.cpp
@@ -778,7 +778,7 @@ tab_chapters::save() {
   wxString err;
 
   try {
-    out = new mm_file_io_c(wxMB(file_name), MODE_WRITE);
+    out = new mm_file_io_c(wxMB(file_name), MODE_CREATE);
 #if defined(SYS_WINDOWS)
     out->use_dos_style_newlines(true);
 #endif