diff --git a/src/calibre/gui2/main.py b/src/calibre/gui2/main.py
index 6924a509b0..e28793b0d0 100644
--- a/src/calibre/gui2/main.py
+++ b/src/calibre/gui2/main.py
@@ -10,7 +10,7 @@ from PyQt5.Qt import (
 
 from calibre import prints, plugins, force_unicode
 from calibre.constants import (iswindows, __appname__, isosx, DEBUG, islinux,
-        filesystem_encoding, get_portable_base)
+        ishaiku, filesystem_encoding, get_portable_base)
 from calibre.utils.ipc import gui_socket_address, RC
 from calibre.gui2 import (
     initialize_file_icon_provider, Application, choose_dir,
diff --git a/src/calibre/utils/lock.py b/src/calibre/utils/lock.py
index 34c8849f8c..52a7bbb99d 100644
--- a/src/calibre/utils/lock.py
+++ b/src/calibre/utils/lock.py
@@ -6,7 +6,7 @@ __docformat__ = 'restructuredtext en'
 Secure access to locked files from multiple processes.
 '''
 
-from calibre.constants import iswindows, __appname__, islinux, win32api, win32event, winerror, fcntl
+from calibre.constants import iswindows, __appname__, islinux, ishaiku, win32api, win32event, winerror, fcntl
 import time, atexit, os, stat, errno
 
 
@@ -228,6 +228,10 @@ elif islinux:
         fcntl.fcntl(fd, fcntl.F_SETFD, old_flags | fcntl.FD_CLOEXEC)
         atexit.register(sock.close)
         return True
+elif ishaiku:
+    def singleinstance(name):
+        # Somebody should fix this.
+        return True
 else:
     def singleinstance_path(name):
         home = os.path.expanduser('~')