diff --git a/ProcessLib/Output/CreateOutput.cpp b/ProcessLib/Output/CreateOutput.cpp
index 27bdb5fba71b9ae70841c5ec8dfeae98f3a78f13..0d320c0b884eeb7028605f61b5f219fb774bb7b4 100644
--- a/ProcessLib/Output/CreateOutput.cpp
+++ b/ProcessLib/Output/CreateOutput.cpp
@@ -117,7 +117,7 @@ std::unique_ptr<Output> createOutput(
             OGS_FATAL(
                 "There are multiple meshes defined in the output section of "
                 "the project file, but the prefix doesn't contain "
-                "'{:meshname}'. Thus the names for the files, the simulation "
+                "'{{:meshname}}'. Thus the names for the files, the simulation "
                 "results should be written to, would not be distinguishable "
                 "for different meshes.");
         }