diff --git a/src/caosdb/file_transmission/file_reader.cpp b/src/caosdb/file_transmission/file_reader.cpp
index f118eca01c6d17975684a15de56eb7c693fdc117..1a78e5a76513ae0aaf94b2ae4967af5d7b66e0c0 100644
--- a/src/caosdb/file_transmission/file_reader.cpp
+++ b/src/caosdb/file_transmission/file_reader.cpp
@@ -59,7 +59,7 @@ FileReader::FileReader(boost::filesystem::path filename)
 }
 
 void FileReader::openFile() {
-  stream_.open(filename_, std::ios::binary | std::ios::ate);
+  stream_.open(filename_.generic_string(), std::ios::binary | std::ios::ate);
   if (!stream_) {
     throw FileIOError("Can't open file for reading: " + filename_.string());
   }
diff --git a/src/caosdb/file_transmission/file_writer.cpp b/src/caosdb/file_transmission/file_writer.cpp
index 5cf7d3a798942fc2ab9a3fe4a278b0e29d362f6e..2c7f2a6000718366f846a4be61dd5c2144370a65 100644
--- a/src/caosdb/file_transmission/file_writer.cpp
+++ b/src/caosdb/file_transmission/file_writer.cpp
@@ -58,7 +58,7 @@ FileWriter::FileWriter(boost::filesystem::path filename) : filename_(std::move(f
 }
 
 void FileWriter::openFile() {
-  stream_.open(filename_, std::ios::binary | std::ios::trunc);
+  stream_.open(filename_.generic_string(), std::ios::binary | std::ios::trunc);
   if (!stream_) {
     throw FileIOError("Can't open file for writing: " + filename_.string());
   }