diff --git a/src/im/instant_messaging.cpp b/src/im/instant_messaging.cpp
index bda87681700eb5539b9739a708d1d1788880d5c0..718a7ddb6a5990b92bf373e01d0bc27901d4b50a 100644
--- a/src/im/instant_messaging.cpp
+++ b/src/im/instant_messaging.cpp
@@ -56,7 +56,7 @@ endElementCallback(void * /*userData*/, const char * /*name*/)
 bool InstantMessaging::saveMessage(const std::string &message, const std::string &author, const std::string &id, int mode)
 {
     std::ofstream File;
-    std::string filename = "im:" + id;
+    std::string filename = "im_" + id;
     File.open(filename.c_str(), static_cast<std::ios_base::openmode>(mode));
 
     if (!File.good() || !File.is_open())