diff --git a/src/console.cpp b/src/console.cpp
index 96de9ac8b8..56b0014b50 100644
--- a/src/console.cpp
+++ b/src/console.cpp
@@ -112,7 +112,7 @@ void IConsolePrint(TextColour colour_code, const std::string &string)
 
 	if (_network_dedicated) {
 		NetworkAdminConsole("console", str);
-		fprintf(stdout, "%s%s\n", GetLogPrefix(), str);
+		fmt::print("{}{}\n", GetLogPrefix(), str);
 		fflush(stdout);
 		IConsoleWriteToLogFile(str);
 		free(str); // free duplicated string since it's not used anymore
diff --git a/src/debug.cpp b/src/debug.cpp
index b088af9aaa..7a411a1077 100644
--- a/src/debug.cpp
+++ b/src/debug.cpp
@@ -127,14 +127,14 @@ void DebugPrint(const char *level, const std::string &message)
 		static FILE *f = FioFOpenFile("commands-out.log", "wb", AUTOSAVE_DIR);
 		if (f == nullptr) return;
 
-		fprintf(f, "%s%s\n", GetLogPrefix(), message.c_str());
+		fmt::print(f, "{}{}\n", GetLogPrefix(), message);
 		fflush(f);
 #ifdef RANDOM_DEBUG
 	} else if (strcmp(level, "random") == 0) {
 		static FILE *f = FioFOpenFile("random-out.log", "wb", AUTOSAVE_DIR);
 		if (f == nullptr) return;
 
-		fprintf(f, "%s\n", message.c_str());
+		fmt::print(f, "{}\n", message);
 		fflush(f);
 #endif
 	} else {
diff --git a/src/map.cpp b/src/map.cpp
index 52aa621ca0..dfaa6ec866 100644
--- a/src/map.cpp
+++ b/src/map.cpp
@@ -87,7 +87,7 @@ TileIndex TileAdd(TileIndex tile, TileIndexDiff add,
 		seprintf(buf, lastof(buf), "TILE_ADD(%s) when adding 0x%.4X and 0x%.4X failed",
 			exp, (uint32)tile, add);
 #if !defined(_MSC_VER)
-		fprintf(stderr, "%s:%d %s\n", file, line, buf);
+		fmt::print(stderr, "{}:{} {}\n", file, line, buf);
 #else
 		_assert(buf, (char*)file, line);
 #endif
diff --git a/src/openttd.cpp b/src/openttd.cpp
index d7f0d064e8..19a2bc515b 100644
--- a/src/openttd.cpp
+++ b/src/openttd.cpp
@@ -615,13 +615,11 @@ int openttd_main(int argc, char *argv[])
 			_load_check_data.Clear();
 			SaveOrLoadResult res = SaveOrLoad(mgo.opt, SLO_CHECK, DFT_GAME_FILE, SAVE_DIR, false);
 			if (res != SL_OK || _load_check_data.HasErrors()) {
-				fprintf(stderr, "Failed to open savegame\n");
+				fmt::print(stderr, "Failed to open savegame\n");
 				if (_load_check_data.HasErrors()) {
 					InitializeLanguagePacks(); // A language pack is needed for GetString()
-					char buf[256];
 					SetDParamStr(0, _load_check_data.error_msg);
-					GetString(buf, _load_check_data.error, lastof(buf));
-					fprintf(stderr, "%s\n", buf);
+					fmt::print(stderr, "{}\n", GetString(_load_check_data.error));
 				}
 				return ret;
 			}
diff --git a/src/os/macosx/macos.mm b/src/os/macosx/macos.mm
index 9db5cd049f..773c77e32f 100644
--- a/src/os/macosx/macos.mm
+++ b/src/os/macosx/macos.mm
@@ -135,7 +135,7 @@ void ShowMacDialog(const char *title, const char *message, const char *buttonLab
  */
 void ShowMacDialog(const char *title, const char *message, const char *buttonLabel)
 {
-	fprintf(stderr, "%s: %s\n", title, message);
+	fmt::print(stderr, "{}: {}\n", title, message);
 }
 
 #endif
diff --git a/src/os/unix/unix.cpp b/src/os/unix/unix.cpp
index 249020458a..edacf2feaf 100644
--- a/src/os/unix/unix.cpp
+++ b/src/os/unix/unix.cpp
@@ -212,7 +212,7 @@ std::string FS2OTTD(const std::string &name)
 
 void ShowInfoI(const std::string &str)
 {
-	fprintf(stderr, "%s\n", str.c_str());
+	fmt::print(stderr, "{}\n", str);
 }
 
 #if !defined(__APPLE__)
@@ -220,9 +220,9 @@ void ShowOSErrorBox(const char *buf, bool system)
 {
 	/* All unix systems, except OSX. Only use escape codes on a TTY. */
 	if (isatty(fileno(stderr))) {
-		fprintf(stderr, "\033[1;31mError: %s\033[0;39m\n", buf);
+		fmt::print(stderr, "\033[1;31mError: {}\033[0;39m\n", buf);
 	} else {
-		fprintf(stderr, "Error: %s\n", buf);
+		fmt::print(stderr, "Error: {}\n", buf);
 	}
 }
 #endif
diff --git a/src/os/windows/win32.cpp b/src/os/windows/win32.cpp
index b941e642ac..07987cb14d 100644
--- a/src/os/windows/win32.cpp
+++ b/src/os/windows/win32.cpp
@@ -321,7 +321,7 @@ static INT_PTR CALLBACK HelpDialogFunc(HWND wnd, UINT msg, WPARAM wParam, LPARAM
 void ShowInfoI(const std::string &str)
 {
 	if (_has_console) {
-		fprintf(stderr, "%s\n", str.c_str());
+		fmt::print(stderr, "{}\n", str);
 	} else {
 		bool old;
 		ReleaseCapture();
diff --git a/src/script/squirrel.cpp b/src/script/squirrel.cpp
index 530e0c32d9..62542ad856 100644
--- a/src/script/squirrel.cpp
+++ b/src/script/squirrel.cpp
@@ -221,7 +221,7 @@ void Squirrel::ErrorPrintFunc(HSQUIRRELVM vm, const std::string &s)
 	/* Check if we have a custom print function */
 	SQPrintFunc *func = ((Squirrel *)sq_getforeignptr(vm))->print_func;
 	if (func == nullptr) {
-		fprintf(stderr, "%s", s.c_str());
+		fmt::print(stderr, "{}", s);
 	} else {
 		(*func)(true, s);
 	}
@@ -238,7 +238,7 @@ void Squirrel::RunError(HSQUIRRELVM vm, const SQChar *error)
 	Squirrel *engine = (Squirrel *)sq_getforeignptr(vm);
 	SQPrintFunc *func = engine->print_func;
 	if (func == nullptr) {
-		fprintf(stderr, "%s", msg.c_str());
+		fmt::print(stderr, "{}", msg);
 	} else {
 		(*func)(true, msg);
 	}
diff --git a/src/settingsgen/settingsgen.cpp b/src/settingsgen/settingsgen.cpp
index 603278859d..273d414b0c 100644
--- a/src/settingsgen/settingsgen.cpp
+++ b/src/settingsgen/settingsgen.cpp
@@ -29,7 +29,7 @@
  */
 void NORETURN FatalErrorI(const std::string &msg)
 {
-	fprintf(stderr, "settingsgen: FATAL: %s\n", msg.c_str());
+	fmt::print(stderr, "settingsgen: FATAL: {}\n", msg);
 	exit(1);
 }
 
@@ -483,7 +483,7 @@ int CDECL main(int argc, char *argv[])
 				break;
 
 			case -2:
-				fprintf(stderr, "Invalid arguments\n");
+				fmt::print(stderr, "Invalid arguments\n");
 				return 1;
 		}
 	}
diff --git a/src/strgen/strgen.cpp b/src/strgen/strgen.cpp
index fc58f8a142..3f7b181e7a 100644
--- a/src/strgen/strgen.cpp
+++ b/src/strgen/strgen.cpp
@@ -34,41 +34,41 @@
 
 
 #ifdef _MSC_VER
-# define LINE_NUM_FMT(s) "%s (%d): warning: %s (" s ")\n"
+# define LINE_NUM_FMT(s) "{} ({}): warning: {} (" s ")\n"
 #else
-# define LINE_NUM_FMT(s) "%s:%d: " s ": %s\n"
+# define LINE_NUM_FMT(s) "{}:{}: " s ": {}\n"
 #endif
 
 void StrgenWarningI(const std::string &msg)
 {
 	if (_show_todo > 0) {
-		fprintf(stderr, LINE_NUM_FMT("warning"), _file, _cur_line, msg.c_str());
+		fmt::print(stderr, LINE_NUM_FMT("warning"), _file, _cur_line, msg);
 	} else {
-		fprintf(stderr, LINE_NUM_FMT("info"), _file, _cur_line, msg.c_str());
+		fmt::print(stderr, LINE_NUM_FMT("info"), _file, _cur_line, msg);
 	}
 	_warnings++;
 }
 
 void StrgenErrorI(const std::string &msg)
 {
-	fprintf(stderr, LINE_NUM_FMT("error"), _file, _cur_line, msg.c_str());
+	fmt::print(stderr, LINE_NUM_FMT("error"), _file, _cur_line, msg);
 	_errors++;
 }
 
 void NORETURN StrgenFatalI(const std::string &msg)
 {
-	fprintf(stderr, LINE_NUM_FMT("FATAL"), _file, _cur_line, msg.c_str());
+	fmt::print(stderr, LINE_NUM_FMT("FATAL"), _file, _cur_line, msg);
 #ifdef _MSC_VER
-	fprintf(stderr, LINE_NUM_FMT("warning"), _file, _cur_line, "language is not compiled");
+	fmt::print(stderr, LINE_NUM_FMT("warning"), _file, _cur_line, "language is not compiled");
 #endif
 	throw std::exception();
 }
 
 void NORETURN FatalErrorI(const std::string &msg)
 {
-	fprintf(stderr, LINE_NUM_FMT("FATAL"), _file, _cur_line, msg.c_str());
+	fmt::print(stderr, LINE_NUM_FMT("FATAL"), _file, _cur_line, msg);
 #ifdef _MSC_VER
-	fprintf(stderr, LINE_NUM_FMT("warning"), _file, _cur_line, "language is not compiled");
+	fmt::print(stderr, LINE_NUM_FMT("warning"), _file, _cur_line, "language is not compiled");
 #endif
 	exit(2);
 }
@@ -266,9 +266,9 @@ struct HeaderFileWriter : HeaderWriter, FileWriter {
 	HeaderFileWriter(const char *filename) : FileWriter("tmp.xxx"),
 		real_filename(stredup(filename)), prev(0), total_strings(0)
 	{
-		fprintf(this->fh, "/* This file is automatically generated. Do not modify */\n\n");
-		fprintf(this->fh, "#ifndef TABLE_STRINGS_H\n");
-		fprintf(this->fh, "#define TABLE_STRINGS_H\n");
+		fmt::print(this->fh, "/* This file is automatically generated. Do not modify */\n\n");
+		fmt::print(this->fh, "#ifndef TABLE_STRINGS_H\n");
+		fmt::print(this->fh, "#define TABLE_STRINGS_H\n");
 	}
 
 	/** Free the filename. */
@@ -279,8 +279,8 @@ struct HeaderFileWriter : HeaderWriter, FileWriter {
 
 	void WriteStringID(const char *name, int stringid)
 	{
-		if (prev + 1 != stringid) fprintf(this->fh, "\n");
-		fprintf(this->fh, "static const StringID %s = 0x%X;\n", name, stringid);
+		if (prev + 1 != stringid) fmt::print(this->fh, "\n");
+		fmt::print(this->fh, "static const StringID {} = 0x{:X};\n", name, stringid);
 		prev = stringid;
 		total_strings++;
 	}
@@ -293,17 +293,17 @@ struct HeaderFileWriter : HeaderWriter, FileWriter {
 			max_plural_forms = std::max(max_plural_forms, _plural_forms[i].plural_count);
 		}
 
-		fprintf(this->fh,
+		fmt::print(this->fh,
 			"\n"
-			"static const uint LANGUAGE_PACK_VERSION     = 0x%X;\n"
-			"static const uint LANGUAGE_MAX_PLURAL       = %u;\n"
-			"static const uint LANGUAGE_MAX_PLURAL_FORMS = %d;\n"
-			"static const uint LANGUAGE_TOTAL_STRINGS    = %u;\n"
+			"static const uint LANGUAGE_PACK_VERSION     = 0x{:X};\n"
+			"static const uint LANGUAGE_MAX_PLURAL       = {};\n"
+			"static const uint LANGUAGE_MAX_PLURAL_FORMS = {};\n"
+			"static const uint LANGUAGE_TOTAL_STRINGS    = {};\n"
 			"\n",
-			(uint)data.Version(), (uint)lengthof(_plural_forms), max_plural_forms, total_strings
+			data.Version(), lengthof(_plural_forms), max_plural_forms, total_strings
 		);
 
-		fprintf(this->fh, "#endif /* TABLE_STRINGS_H */\n");
+		fmt::print(this->fh, "#endif /* TABLE_STRINGS_H */\n");
 
 		this->FileWriter::Finalise();
 
@@ -493,7 +493,7 @@ int CDECL main(int argc, char *argv[])
 				break;
 
 			case -2:
-				fprintf(stderr, "Invalid arguments\n");
+				fmt::print(stderr, "Invalid arguments\n");
 				return 0;
 		}
 	}
@@ -556,7 +556,7 @@ int CDECL main(int argc, char *argv[])
 
 				/* if showing warnings, print a summary of the language */
 				if ((_show_todo & 2) != 0) {
-					fprintf(stdout, "%d warnings and %d errors for %s\n", _warnings, _errors, pathbuf);
+					fmt::print("{} warnings and {} errors for {}\n", _warnings, _errors, pathbuf);
 				}
 			}
 		}
diff --git a/src/video/cocoa/cocoa_wnd.mm b/src/video/cocoa/cocoa_wnd.mm
index 88361dbc7a..df08df857f 100644
--- a/src/video/cocoa/cocoa_wnd.mm
+++ b/src/video/cocoa/cocoa_wnd.mm
@@ -397,7 +397,7 @@ void CocoaDialog(const char *title, const char *message, const char *buttonLabel
 	if (VideoDriver::GetInstance() == nullptr) {
 		CocoaSetupApplication(); // Setup application before showing dialog
 	} else if (!_cocoa_video_started && VideoDriver::GetInstance()->Start({}) != nullptr) {
-		fprintf(stderr, "%s: %s\n", title, message);
+		fmt::print(stderr, "{}: {}\n", title, message);
 		return;
 	}