diff --git a/src/event/Thread.cxx b/src/event/Thread.cxx
index b5d4127b8..e5b1ecccd 100644
--- a/src/event/Thread.cxx
+++ b/src/event/Thread.cxx
@@ -62,7 +62,7 @@ EventThread::Run() noexcept
 			SetThreadRealtime();
 		} catch (...) {
 			FmtInfo(event_domain,
-				"RTIOThread could not get realtime scheduling, continuing anyway: %s",
+				"RTIOThread could not get realtime scheduling, continuing anyway: {}",
 				std::current_exception());
 		}
 	}
diff --git a/src/input/Init.cxx b/src/input/Init.cxx
index 97f96f8d3..235b29e3c 100644
--- a/src/input/Init.cxx
+++ b/src/input/Init.cxx
@@ -71,12 +71,12 @@ input_stream_global_init(const ConfigData &config, EventLoop &event_loop)
 			input_plugins_enabled[i] = true;
 		} catch (const PluginUnconfigured &e) {
 			FmtDebug(input_domain,
-				 "Input plugin '{}' is not configured: %s",
+				 "Input plugin '{}' is not configured: {}",
 				 plugin->name, e.what());
 			continue;
 		} catch (const PluginUnavailable &e) {
 			FmtDebug(input_domain,
-				 "Input plugin '{}' is unavailable: %s",
+				 "Input plugin '{}' is unavailable: {}",
 				 plugin->name, e.what());
 			continue;
 		} catch (...) {
diff --git a/src/output/Thread.cxx b/src/output/Thread.cxx
index 4eb687cd2..20eab79b1 100644
--- a/src/output/Thread.cxx
+++ b/src/output/Thread.cxx
@@ -435,7 +435,7 @@ AudioOutputControl::Task() noexcept
 		SetThreadRealtime();
 	} catch (...) {
 		FmtInfo(output_domain,
-			"OutputThread could not get realtime scheduling, continuing anyway: %s",
+			"OutputThread could not get realtime scheduling, continuing anyway: {}",
 			std::current_exception());
 	}
 
diff --git a/src/output/plugins/FifoOutputPlugin.cxx b/src/output/plugins/FifoOutputPlugin.cxx
index f5f7e81c5..12869cca9 100644
--- a/src/output/plugins/FifoOutputPlugin.cxx
+++ b/src/output/plugins/FifoOutputPlugin.cxx
@@ -195,7 +195,7 @@ FifoOutput::Cancel() noexcept
 
 	if (bytes < 0 && errno != EAGAIN) {
 		FmtError(fifo_output_domain,
-			 "Flush of FIFO \"{}\" failed: %s",
+			 "Flush of FIFO \"{}\" failed: {}",
 			 path_utf8, strerror(errno));
 	}
 }