diff --git a/picard/formats/__init__.py b/picard/formats/__init__.py
index 63d66242d..d737b809f 100644
--- a/picard/formats/__init__.py
+++ b/picard/formats/__init__.py
@@ -86,107 +86,6 @@ def open(filename):
         return None
 
 
-def _insert_bytes_no_mmap(fobj, size, offset, BUFFER_SIZE=2**16):
-    """Insert size bytes of empty space starting at offset.
-
-    fobj must be an open file object, open rb+ or
-    equivalent. Mutagen tries to use mmap to resize the file, but
-    falls back to a significantly slower method if mmap fails.
-    """
-    assert 0 < size
-    assert 0 <= offset
-    locked = False
-    fobj.seek(0, 2)
-    filesize = fobj.tell()
-    movesize = filesize - offset
-    fobj.write('\x00' * size)
-    fobj.flush()
-    try:
-        locked = _win32_locking(fobj, filesize, msvcrt.LK_LOCK)
-        fobj.truncate(filesize)
-
-        fobj.seek(0, 2)
-        padsize = size
-        # Don't generate an enormous string if we need to pad
-        # the file out several megs.
-        while padsize:
-            addsize = min(BUFFER_SIZE, padsize)
-            fobj.write("\x00" * addsize)
-            padsize -= addsize
-
-        fobj.seek(filesize, 0)
-        while movesize:
-            # At the start of this loop, fobj is pointing at the end
-            # of the data we need to move, which is of movesize length.
-            thismove = min(BUFFER_SIZE, movesize)
-            # Seek back however much we're going to read this frame.
-            fobj.seek(-thismove, 1)
-            nextpos = fobj.tell()
-            # Read it, so we're back at the end.
-            data = fobj.read(thismove)
-            # Seek back to where we need to write it.
-            fobj.seek(-thismove + size, 1)
-            # Write it.
-            fobj.write(data)
-            # And seek back to the end of the unmoved data.
-            fobj.seek(nextpos)
-            movesize -= thismove
-
-        fobj.flush()
-    finally:
-        if locked:
-            _win32_locking(fobj, filesize, msvcrt.LK_UNLCK)
-
-
-def _delete_bytes_no_mmap(fobj, size, offset, BUFFER_SIZE=2**16):
-    """Delete size bytes of empty space starting at offset.
-
-    fobj must be an open file object, open rb+ or
-    equivalent. Mutagen tries to use mmap to resize the file, but
-    falls back to a significantly slower method if mmap fails.
-    """
-    locked = False
-    assert 0 < size
-    assert 0 <= offset
-    fobj.seek(0, 2)
-    filesize = fobj.tell()
-    movesize = filesize - offset - size
-    assert 0 <= movesize
-    try:
-        if movesize > 0:
-            fobj.flush()
-            locked = _win32_locking(fobj, filesize, msvcrt.LK_LOCK)
-            fobj.seek(offset + size)
-            buf = fobj.read(BUFFER_SIZE)
-            while buf:
-                fobj.seek(offset)
-                fobj.write(buf)
-                offset += len(buf)
-                fobj.seek(offset + size)
-                buf = fobj.read(BUFFER_SIZE)
-        fobj.truncate(filesize - size)
-        fobj.flush()
-    finally:
-        if locked:
-            _win32_locking(fobj, filesize, msvcrt.LK_UNLCK)
-
-
-def _win32_locking(fobj, nbytes, mode):
-    try:
-        fobj.seek(0)
-        msvcrt.locking(fobj.fileno(), mode, nbytes)
-    except IOError:
-        return False
-    else:
-        return True
-
-
-if sys.platform == 'win32':
-    import msvcrt
-    _util.insert_bytes = _insert_bytes_no_mmap
-    _util.delete_bytes = _delete_bytes_no_mmap
-
-
 from picard.formats.id3 import (
     AiffFile,
     MP3File,