diff --git a/src/random_access_file.cpp b/src/random_access_file.cpp
--- a/src/random_access_file.cpp
+++ b/src/random_access_file.cpp
@@ -11,6 +11,7 @@
 #include "random_access_file_type.h"
 
 #include "debug.h"
+#include "error_func.h"
 #include "fileio_func.h"
 #include "string_func.h"
 
@@ -24,11 +25,11 @@
 RandomAccessFile::RandomAccessFile(const std::string &filename, Subdirectory subdir) : filename(filename)
 {
 	this->file_handle = FioFOpenFile(filename, "rb", subdir);
-	if (this->file_handle == nullptr) usererror("Cannot open file '%s'", filename.c_str());
+	if (this->file_handle == nullptr) UserError("Cannot open file '{}'", filename);
 
 	/* When files are in a tar-file, the begin of the file might not be at 0. */
 	long pos = ftell(this->file_handle);
-	if (pos < 0) usererror("Cannot read file '%s'", filename.c_str());
+	if (pos < 0) UserError("Cannot read file '{}'", filename);
 
 	/* Store the filename without path and extension */
 	auto t = filename.rfind(PATHSEPCHAR);