diff --git a/src/Buffer.cpp b/src/Buffer.cpp
index 7ea74bdb22..f218e99049 100644
--- a/src/Buffer.cpp
+++ b/src/Buffer.cpp
@@ -817,7 +817,7 @@ bool Buffer::save() const
 			backupName = FileName(addName(lyxrc.backupdir_path,
 						      mangledName));
 		}
-		if (fileName().copyTo(backupName, true)) {
+		if (fileName().copyTo(backupName)) {
 			madeBackup = true;
 		} else {
 			Alert::error(_("Backup failure"),
diff --git a/src/EmbeddedFiles.cpp b/src/EmbeddedFiles.cpp
index d8756b1d9e..6c6fffec4d 100644
--- a/src/EmbeddedFiles.cpp
+++ b/src/EmbeddedFiles.cpp
@@ -142,7 +142,7 @@ bool EmbeddedFile::extract(Buffer const * buf) const
 		return false;
 	}
 
-	if (emb.copyTo(ext, true))
+	if (emb.copyTo(ext))
 		return true;
 
 	Alert::error(_("Copy file failure"),
@@ -184,7 +184,7 @@ bool EmbeddedFile::updateFromExternalFile(Buffer const * buf) const
 	FileName path = emb.onlyPath();
 	if (!path.isDirectory())
 		path.createPath();
-	if (ext.copyTo(emb, true))
+	if (ext.copyTo(emb))
 		return true;
 	Alert::error(_("Copy file failure"),
 		 bformat(_("Cannot copy file %1$s to %2$s.\n"
@@ -287,7 +287,7 @@ bool EmbeddedFiles::writeFile(DocFileName const & filename)
 
 	::zipFiles(zipfile.toFilesystemEncoding(), filenames);
 	// copy file back
-	if (!zipfile.copyTo(filename, true)) {
+	if (!zipfile.copyTo(filename)) {
 		Alert::error(_("Save failure"),
 				 bformat(_("Cannot create file %1$s.\n"
 					   "Please check whether the directory exists and is writeable."),
diff --git a/src/Mover.cpp b/src/Mover.cpp
index 28f2ce950a..990a550cb6 100644
--- a/src/Mover.cpp
+++ b/src/Mover.cpp
@@ -35,7 +35,7 @@ bool Mover::copy(FileName const & from, FileName const & to) const
 bool Mover::do_copy(FileName const & from, FileName const & to,
 		    string const &) const
 {
-	return from.copyTo(to, true);
+	return from.copyTo(to);
 }
 
 
diff --git a/src/insets/InsetBibtex.cpp b/src/insets/InsetBibtex.cpp
index 23be923ad0..9f9d21398a 100644
--- a/src/insets/InsetBibtex.cpp
+++ b/src/insets/InsetBibtex.cpp
@@ -179,7 +179,7 @@ int InsetBibtex::latex(Buffer const & buffer, odocstream & os,
 			FileName const out_file = makeAbsPath(database + ".bib",
 					buffer.masterBuffer()->temppath());
 
-			bool const success = in_file.copyTo(out_file, true);
+			bool const success = in_file.copyTo(out_file);
 			if (!success) {
 				lyxerr << "Failed to copy '" << in_file
 				       << "' to '" << out_file << "'"
@@ -238,7 +238,7 @@ int InsetBibtex::latex(Buffer const & buffer, odocstream & os,
 			base = removeExtension(in_file.mangledFilename());
 			FileName const out_file(makeAbsPath(base + ".bst",
 					buffer.masterBuffer()->temppath()));
-			bool const success = in_file.copyTo(out_file, true);
+			bool const success = in_file.copyTo(out_file);
 			if (!success) {
 				lyxerr << "Failed to copy '" << in_file
 				       << "' to '" << out_file << "'"
diff --git a/src/insets/InsetInclude.cpp b/src/insets/InsetInclude.cpp
index a983854715..b6a4f0bc6d 100644
--- a/src/insets/InsetInclude.cpp
+++ b/src/insets/InsetInclude.cpp
@@ -475,7 +475,7 @@ int InsetInclude::latex(Buffer const & buffer, odocstream & os,
 		unsigned long const checksum_out = writefile.checksum();
 
 		if (checksum_in != checksum_out) {
-			if (!included_file.copyTo(writefile, true)) {
+			if (!included_file.copyTo(writefile)) {
 				// FIXME UNICODE
 				LYXERR(Debug::LATEX,
 					to_utf8(bformat(_("Could not copy the file\n%1$s\n"
diff --git a/src/support/FileName.cpp b/src/support/FileName.cpp
index e0e10cf07f..1b4a545f3f 100644
--- a/src/support/FileName.cpp
+++ b/src/support/FileName.cpp
@@ -139,10 +139,9 @@ void FileName::erase()
 }
 
 
-bool FileName::copyTo(FileName const & name, bool overwrite) const
+bool FileName::copyTo(FileName const & name) const
 {
-	if (overwrite)
-		QFile::remove(name.d->fi.absoluteFilePath());
+	QFile::remove(name.d->fi.absoluteFilePath());
 	bool success = QFile::copy(d->fi.absoluteFilePath(), name.d->fi.absoluteFilePath());
 	if (!success)
 		lyxerr << "FileName::copyTo(): Could not copy file "
diff --git a/src/support/FileName.h b/src/support/FileName.h
index fd63ce5e53..dd3932a2dd 100644
--- a/src/support/FileName.h
+++ b/src/support/FileName.h
@@ -90,9 +90,9 @@ public:
 	
 	/// copy a file
 	/// \return true when file/directory is writable (write test file)
-	/// \param overwrite: set to true if we should erase the \c target 
-	/// file if it exists,
-	bool copyTo(FileName const & target, bool overwrite = false) const;
+	/// \warning This methods has different semantics when system level
+	/// copy command, it will overwrite the \c target file if it exists,
+	bool copyTo(FileName const & target) const;
 
 	/// remove pointed file.
 	/// \return true on success.