diff --git a/src/buffer.C b/src/buffer.C
index e087722523..e3e2ea27e5 100644
--- a/src/buffer.C
+++ b/src/buffer.C
@@ -829,7 +829,7 @@ bool Buffer::do_writeFile(ostream & ofs) const
 }
 
 
-bool Buffer::makeLaTeXFile(string const & fname,
+bool Buffer::makeLaTeXFile(FileName const & fname,
 			   string const & original_path,
 			   OutputParams const & runparams,
 			   bool output_preamble, bool output_body)
@@ -1025,7 +1025,7 @@ bool Buffer::isDocBook() const
 }
 
 
-void Buffer::makeDocBookFile(string const & fname,
+void Buffer::makeDocBookFile(FileName const & fname,
 			      OutputParams const & runparams,
 			      bool const body_only)
 {
@@ -1036,7 +1036,7 @@ void Buffer::makeDocBookFile(string const & fname,
 	if (!openFileWrite(ofs, fname))
 		return;
 
-	writeDocBookSource(ofs, fname, runparams, body_only);
+	writeDocBookSource(ofs, fname.absFilename(), runparams, body_only);
 
 	ofs.close();
 	if (ofs.fail())
@@ -1124,7 +1124,7 @@ int Buffer::runChktex()
 	busy(true);
 
 	// get LaTeX-Filename
-	string const name = getLatexName();
+	string const name = getLatexName(false);
 	string const path = temppath();
 	string const org_path = filePath();
 
@@ -1135,10 +1135,10 @@ int Buffer::runChktex()
 	OutputParams runparams;
 	runparams.flavor = OutputParams::LATEX;
 	runparams.nice = false;
-	makeLaTeXFile(name, org_path, runparams);
+	makeLaTeXFile(FileName(name), org_path, runparams);
 
 	TeXErrors terr;
-	Chktex chktex(lyxrc.chktex_command, name, filePath());
+	Chktex chktex(lyxrc.chktex_command, onlyFilename(name), filePath());
 	int const res = chktex.run(terr); // run chktex
 
 	if (res == -1) {
diff --git a/src/buffer.h b/src/buffer.h
index 6b6addc10b..f37336790b 100644
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -147,7 +147,7 @@ public:
 	bool writeFile(support::FileName const &) const;
 
 	/// Just a wrapper for the method below, first creating the ofstream.
-	bool makeLaTeXFile(std::string const & filename,
+	bool makeLaTeXFile(support::FileName const & filename,
 			   std::string const & original_path,
 			   OutputParams const &,
 			   bool output_preamble = true,
@@ -159,7 +159,7 @@ public:
 			   bool output_preamble = true,
 			   bool output_body = true);
 	///
-	void makeDocBookFile(std::string const & filename,
+	void makeDocBookFile(support::FileName const & filename,
 			     OutputParams const & runparams_in,
 			     bool only_body = false);
 	///
diff --git a/src/bufferlist.C b/src/bufferlist.C
index aa532e98b3..1d14c077d3 100644
--- a/src/bufferlist.C
+++ b/src/bufferlist.C
@@ -319,7 +319,7 @@ void BufferList::updateIncludedTeXfiles(string const & mastertmpdir,
 			string writefile = mastertmpdir;
 			writefile += '/';
 			writefile += (*it)->getLatexName();
-			(*it)->makeLaTeXFile(writefile, mastertmpdir,
+			(*it)->makeLaTeXFile(FileName(writefile), mastertmpdir,
 					     runparams, false);
 			(*it)->markDepClean(mastertmpdir);
 		}
diff --git a/src/exporter.C b/src/exporter.C
index 0956e100d2..853e8b7db1 100644
--- a/src/exporter.C
+++ b/src/exporter.C
@@ -192,19 +192,19 @@ bool Exporter::Export(Buffer * buffer, string const & format,
 
 	// Ascii backend
 	if (backend_format == "text")
-		writeFileAscii(*buffer, filename, runparams);
+		writeFileAscii(*buffer, FileName(filename), runparams);
 	// no backend
 	else if (backend_format == "lyx")
 		buffer->writeFile(FileName(filename));
 	// Docbook backend
 	else if (buffer->isDocBook()) {
 		runparams.nice = !put_in_tempdir;
-		buffer->makeDocBookFile(filename, runparams);
+		buffer->makeDocBookFile(FileName(filename), runparams);
 	}
 	// LaTeX backend
 	else if (backend_format == format) {
 		runparams.nice = true;
-		if (!buffer->makeLaTeXFile(filename, string(), runparams))
+		if (!buffer->makeLaTeXFile(FileName(filename), string(), runparams))
 			return false;
 	} else if (!lyxrc.tex_allows_spaces
 		   && contains(buffer->filePath(), ' ')) {
@@ -213,7 +213,7 @@ bool Exporter::Export(Buffer * buffer, string const & format,
 		return false;
 	} else {
 		runparams.nice = false;
-		if (!buffer->makeLaTeXFile(filename, buffer->filePath(), runparams))
+		if (!buffer->makeLaTeXFile(FileName(filename), buffer->filePath(), runparams))
 			return false;
 	}
 
diff --git a/src/graphics/PreviewLoader.C b/src/graphics/PreviewLoader.C
index f964ca09fc..840914a971 100644
--- a/src/graphics/PreviewLoader.C
+++ b/src/graphics/PreviewLoader.C
@@ -568,12 +568,12 @@ void PreviewLoader::Impl::startLoading()
 	pending_.clear();
 
 	// Output the LaTeX file.
-	string const latexfile = filename_base + ".tex";
+	FileName const latexfile(filename_base + ".tex");
 
 	// FIXME UNICODE
 	// This creates an utf8 encoded file, but the proper inputenc
 	// command is missing.
-	odocfstream of(latexfile.c_str());
+	odocfstream of(latexfile.toFilesystemEncoding().c_str());
 	if (!of) {
 		lyxerr[Debug::GRAPHICS] << "PreviewLoader::startLoading()\n"
 					<< "Unable to create LaTeX file\n"
@@ -590,7 +590,7 @@ void PreviewLoader::Impl::startLoading()
 	// The conversion command.
 	ostringstream cs;
 	cs << pconverter_->command << ' ' << pconverter_->to << ' '
-	   << support::quoteName(latexfile) << ' '
+	   << support::quoteName(latexfile.toFilesystemEncoding()) << ' '
 	   << int(font_scaling_factor_) << ' '
 	   << theApp()->hexName(LColor::preview) << ' '
 	   << theApp()->hexName(LColor::background);
diff --git a/src/insets/insetinclude.C b/src/insets/insetinclude.C
index 5cee1b1f15..c1fec50560 100644
--- a/src/insets/insetinclude.C
+++ b/src/insets/insetinclude.C
@@ -428,7 +428,7 @@ int InsetInclude::latex(Buffer const & buffer, odocstream & os,
 // argument. Should we set it to string(), or should makeLaTeXFile
 // make use of it somehow? (JMarc 20031002)
 #endif
-		tmp->makeLaTeXFile(writefile.absFilename(),
+		tmp->makeLaTeXFile(writefile,
 				   onlyPath(masterFilename(buffer)),
 				   runparams, false);
 	} else {
@@ -535,7 +535,7 @@ int InsetInclude::docbook(Buffer const & buffer, odocstream & os,
 		lyxerr[Debug::LATEX] << "exportfile:" << exportfile << endl;
 		lyxerr[Debug::LATEX] << "writefile:" << writefile << endl;
 
-		tmp->makeDocBookFile(writefile.absFilename(), runparams, true);
+		tmp->makeDocBookFile(writefile, runparams, true);
 	}
 
 	runparams.exportdata->addExternalFile("docbook", writefile,
diff --git a/src/output.C b/src/output.C
index ab1177b974..7b19e0b091 100644
--- a/src/output.C
+++ b/src/output.C
@@ -22,6 +22,7 @@
 namespace lyx {
 
 using support::bformat;
+using support::FileName;
 using support::makeDisplayPath;
 
 using std::ofstream;
@@ -30,11 +31,11 @@ using std::string;
 namespace {
 
 template<typename OFStream>
-bool doOpenFileWrite(OFStream & ofs, string const & fname)
+bool doOpenFileWrite(OFStream & ofs, FileName const & fname)
 {
-	ofs.open(fname.c_str());
+	ofs.open(fname.toFilesystemEncoding().c_str());
 	if (!ofs) {
-		docstring const file = makeDisplayPath(fname, 50);
+		docstring const file = makeDisplayPath(fname.absFilename(), 50);
 		docstring text = bformat(_("Could not open the specified "
 						     "document\n%1$s."), file);
 		frontend::Alert::error(_("Could not open file"), text);
@@ -46,13 +47,13 @@ bool doOpenFileWrite(OFStream & ofs, string const & fname)
 }
 
 
-bool openFileWrite(ofstream & ofs, string const & fname)
+bool openFileWrite(ofstream & ofs, FileName const & fname)
 {
 	return doOpenFileWrite(ofs, fname);
 }
 
 
-bool openFileWrite(odocfstream & ofs, string const & fname)
+bool openFileWrite(odocfstream & ofs, FileName const & fname)
 {
 	return doOpenFileWrite(ofs, fname);
 }
diff --git a/src/output.h b/src/output.h
index b2294e6de6..fea5e1bb04 100644
--- a/src/output.h
+++ b/src/output.h
@@ -17,8 +17,10 @@
 
 namespace lyx {
 
-bool openFileWrite(std::ofstream & ofs, std::string const & fname);
-bool openFileWrite(odocfstream & ofs, std::string const & fname);
+namespace support { class FileName; }
+
+bool openFileWrite(std::ofstream & ofs, support::FileName const & fname);
+bool openFileWrite(odocfstream & ofs, support::FileName const & fname);
 
 
 } // namespace lyx
diff --git a/src/output_plaintext.C b/src/output_plaintext.C
index de102dc40d..46e3990ce1 100644
--- a/src/output_plaintext.C
+++ b/src/output_plaintext.C
@@ -22,6 +22,7 @@
 #include "ParagraphList.h"
 #include "ParagraphParameters.h"
 
+#include "support/filename.h"
 #include "support/lstrings.h"
 
 
@@ -31,6 +32,7 @@ using support::ascii_lowercase;
 using support::compare_ascii_no_case;
 using support::compare_no_case;
 using support::contains;
+using support::FileName;
 
 using std::endl;
 using std::ostream;
@@ -38,7 +40,7 @@ using std::pair;
 using std::string;
 
 
-void writeFileAscii(Buffer const & buf, string const & fname,
+void writeFileAscii(Buffer const & buf, FileName const & fname,
 	OutputParams const & runparams)
 {
 	odocfstream ofs;
diff --git a/src/output_plaintext.h b/src/output_plaintext.h
index 16eb1414f1..682a94794f 100644
--- a/src/output_plaintext.h
+++ b/src/output_plaintext.h
@@ -17,13 +17,15 @@
 
 namespace lyx {
 
+namespace support { class FileName; }
+
 class Buffer;
 class OutputParams;
 class Paragraph;
 
 
 ///
-void writeFileAscii(Buffer const & buf, std::string const &,
+void writeFileAscii(Buffer const & buf, support::FileName const &,
 	OutputParams const &);
 
 ///
diff --git a/src/tex2lyx/tex2lyx.C b/src/tex2lyx/tex2lyx.C
index 3ca623d1d2..8f618672bf 100644
--- a/src/tex2lyx/tex2lyx.C
+++ b/src/tex2lyx/tex2lyx.C
@@ -456,17 +456,16 @@ void tex2lyx(std::istream &is, std::ostream &os)
 
 
 /// convert TeX from \p infilename to LyX and write it to \p os
-bool tex2lyx(string const &infilename, std::ostream &os)
+bool tex2lyx(FileName const & infilename, std::ostream &os)
 {
-	BOOST_ASSERT(lyx::support::absolutePath(infilename));
-	ifstream is(infilename.c_str());
+	ifstream is(infilename.toFilesystemEncoding().c_str());
 	if (!is.good()) {
 		cerr << "Could not open input file \"" << infilename
 		     << "\" for reading." << endl;
 		return false;
 	}
 	string const oldParentFilePath = parentFilePath;
-	parentFilePath = onlyPath(infilename);
+	parentFilePath = onlyPath(infilename.absFilename());
 	tex2lyx(is, os);
 	parentFilePath = oldParentFilePath;
 	return true;
@@ -499,7 +498,7 @@ bool tex2lyx(string const &infilename, FileName const &outfilename)
 	cerr << "Input file: " << infilename << "\n";
 	cerr << "Output file: " << outfilename << "\n";
 #endif
-	return tex2lyx(infilename, os);
+	return tex2lyx(FileName(infilename), os);
 }
 
 } // namespace lyx
@@ -546,7 +545,7 @@ int main(int argc, char * argv[])
 	parentFilePath = masterFilePath;
 
 	if (outfilename == "-") {
-		if (tex2lyx(infilename, cout))
+		if (tex2lyx(FileName(infilename), cout))
 			return EXIT_SUCCESS;
 		else
 			return EXIT_FAILURE;