diff --git a/src/files.c b/src/files.c
index 4da3aebaeba14706566a23e75f87667d7cf3b9ad..ccf1f2a2a1f4f494dcab7d35dedcbb557bbf6ec6 100644
--- a/src/files.c
+++ b/src/files.c
@@ -252,7 +252,8 @@ int write_lockfile(const char *lockfilename, const char *origfilename, bool modi
     snprintf(&lockdata[2], 11, "nano %s", VERSION);
     strncpy(&lockdata[28], mypwuid->pw_name, 16);
     strncpy(&lockdata[68], myhostname, 31);
-    strncpy(&lockdata[108], origfilename, 768);
+    if (origfilename != NULL)
+	strncpy(&lockdata[108], origfilename, 768);
     if (modified == TRUE)
 	lockdata[1007] = 0x55;