diff --git a/libraries/libldap_r/libldap_r.dsp b/libraries/libldap_r/libldap_r.dsp
index 365140f5d2..64d5153297 100644
--- a/libraries/libldap_r/libldap_r.dsp
+++ b/libraries/libldap_r/libldap_r.dsp
@@ -144,6 +144,10 @@ SOURCE=..\libldap\bind.c
 # End Source File
 # Begin Source File
 
+SOURCE=..\libldap\cancel.c
+# End Source File
+# Begin Source File
+
 SOURCE=..\libldap\charray.c
 # End Source File
 # Begin Source File