diff --git a/Source/FileManager/ReplacementCharacters.cs b/Source/FileManager/ReplacementCharacters.cs
index 8609e1b86..22c604f00 100644
--- a/Source/FileManager/ReplacementCharacters.cs
+++ b/Source/FileManager/ReplacementCharacters.cs
@@ -53,6 +53,13 @@ public void Update(char charToReplace, string replacementString, string descript
 	public static Replacement OpenAngleBracket(string replacement) => new('<', replacement, "Open Angle Bracket");
 	public static Replacement CloseAngleBracket(string replacement) => new('>', replacement, "Close Angle Bracket");
 	public static Replacement Pipe(string replacement) => new('|', replacement, "Vertical Line");
+	public static Replacement a_umlaut(string replacement = "ae") => new('ä', replacement, "a umlaut (ä)");
+	public static Replacement o_umlaut(string replacement = "oe") => new('ö', replacement, "o umlaut (ö)");
+	public static Replacement u_umlaut(string replacement = "ue") => new('ü', replacement, "u umlaut (ü)");
+	public static Replacement A_umlaut(string replacement = "Ae") => new('Ä', replacement, "A umlaut (Ä)");
+	public static Replacement O_umlaut(string replacement = "Oe") => new('Ö', replacement, "O umlaut (Ö)");
+	public static Replacement U_umlaut(string replacement = "Ue") => new('Ü', replacement, "U umlaut (Ü)");
+	public static Replacement Eszett(string replacement = "ss") => new('ß', replacement, "Eszett (ß)");
 
 }
 
@@ -92,7 +99,14 @@ public override bool Equals(object? obj)
 				Replacement.Colon("_"),
 				Replacement.Asterisk("✱"),
 				Replacement.QuestionMark("？"),
-				Replacement.Pipe("⏐")]
+				Replacement.Pipe("⏐"),
+				Replacement.a_umlaut(),
+				Replacement.o_umlaut(),
+				Replacement.u_umlaut(),
+				Replacement.A_umlaut(),
+				Replacement.O_umlaut(),
+				Replacement.U_umlaut(),
+				Replacement.Eszett()]
 	};
 
 	private static readonly ReplacementCharacters HiFi_Other = new()
@@ -103,7 +117,14 @@ public override bool Equals(object? obj)
 				Replacement.FilenameBackSlash("\\"),
 				Replacement.OpenQuote("“"),
 				Replacement.CloseQuote("”"),
-				Replacement.OtherQuote("\"")]
+				Replacement.OtherQuote("\""),
+				Replacement.a_umlaut(),
+				Replacement.o_umlaut(),
+				Replacement.u_umlaut(),
+				Replacement.A_umlaut(),
+				Replacement.O_umlaut(),
+				Replacement.U_umlaut(),
+				Replacement.Eszett()]
 	};
 
 	private static readonly ReplacementCharacters LoFi_NTFS = new()
@@ -117,7 +138,14 @@ public override bool Equals(object? obj)
 				Replacement.OtherQuote("'"),
 				Replacement.OpenAngleBracket("{"),
 				Replacement.CloseAngleBracket("}"),
-				Replacement.Colon("-")]
+				Replacement.Colon("-"),
+				Replacement.a_umlaut(),
+				Replacement.o_umlaut(),
+				Replacement.u_umlaut(),
+				Replacement.A_umlaut(),
+				Replacement.O_umlaut(),
+				Replacement.U_umlaut(),
+				Replacement.Eszett()]
 	};
 
 	private static readonly ReplacementCharacters LoFi_Other = new()
@@ -128,7 +156,14 @@ public override bool Equals(object? obj)
 				Replacement.FilenameBackSlash("\\"),
 				Replacement.OpenQuote("\""),
 				Replacement.CloseQuote("\""),
-				Replacement.OtherQuote("\"")]
+				Replacement.OtherQuote("\""),
+				Replacement.a_umlaut(),
+				Replacement.o_umlaut(),
+				Replacement.u_umlaut(),
+				Replacement.A_umlaut(),
+				Replacement.O_umlaut(),
+				Replacement.U_umlaut(),
+				Replacement.Eszett()]
 	};
 
 	private static readonly ReplacementCharacters BareBones_NTFS = new()
@@ -139,7 +174,14 @@ public override bool Equals(object? obj)
 				Replacement.FilenameBackSlash("_"),
 				Replacement.OpenQuote("_"),
 				Replacement.CloseQuote("_"),
-				Replacement.OtherQuote("_")]
+				Replacement.OtherQuote("_"),
+				Replacement.a_umlaut(),
+				Replacement.o_umlaut(),
+				Replacement.u_umlaut(),
+				Replacement.A_umlaut(),
+				Replacement.O_umlaut(),
+				Replacement.U_umlaut(),
+				Replacement.Eszett()]
 	};
 
 	private static readonly ReplacementCharacters BareBones_Other = new()
@@ -150,7 +192,14 @@ public override bool Equals(object? obj)
 				Replacement.FilenameBackSlash("\\"),
 				Replacement.OpenQuote("\""),
 				Replacement.CloseQuote("\""),
-				Replacement.OtherQuote("\"")]
+				Replacement.OtherQuote("\""),
+				Replacement.a_umlaut(),
+				Replacement.o_umlaut(),
+				Replacement.u_umlaut(),
+				Replacement.A_umlaut(),
+				Replacement.O_umlaut(),
+				Replacement.U_umlaut(),
+				Replacement.Eszett()]
 	};
 	#endregion
 	/// <summary>
diff --git a/Source/_Tests/FileManager.Tests/FileUtilityTests.cs b/Source/_Tests/FileManager.Tests/FileUtilityTests.cs
index 6c0e7f7bf..753e540c4 100644
--- a/Source/_Tests/FileManager.Tests/FileUtilityTests.cs
+++ b/Source/_Tests/FileManager.Tests/FileUtilityTests.cs
@@ -221,6 +221,48 @@ public void Tests(string input, string extension, string expected, PlatformID pl
 	}
 }
 
+[TestClass]
+public class UmlautReplacements
+{
+	static readonly ReplacementCharacters Default = ReplacementCharacters.Default(true);
+	static readonly ReplacementCharacters LoFi = ReplacementCharacters.LoFiDefault(true);
+	static readonly ReplacementCharacters Barebones = ReplacementCharacters.Barebones(true);
+
+	[TestMethod]
+	[DataRow("Märchen", "Maerchen")]
+	[DataRow("Über den Wolken", "Ueber den Wolken")]
+	[DataRow("schön", "schoen")]
+	[DataRow("grün", "gruen")]
+	[DataRow("Straße", "Strasse")]
+	[DataRow("Ärger", "Aerger")]
+	[DataRow("Ökonom", "Oekonom")]
+	[DataRow("Übel", "Uebel")]
+	public void DefaultPreset_ReplacesUmlauts(string input, string expected)
+		=> Default.ReplaceFilenameChars(input).Should().Be(expected);
+
+	[TestMethod]
+	[DataRow("Märchen", "Maerchen")]
+	[DataRow("Straße", "Strasse")]
+	public void LoFiPreset_ReplacesUmlauts(string input, string expected)
+		=> LoFi.ReplaceFilenameChars(input).Should().Be(expected);
+
+	[TestMethod]
+	[DataRow("Märchen", "Maerchen")]
+	[DataRow("Straße", "Strasse")]
+	public void BarebonesPreset_ReplacesUmlauts(string input, string expected)
+		=> Barebones.ReplaceFilenameChars(input).Should().Be(expected);
+
+	// Regression guard: the Defaults block once had its ASCII string delimiters
+	// auto-formatted into curly quotes (U+201C/U+201D), which broke compilation.
+	// Pin the actual Unicode replacement codepoints so a future re-corruption
+	// is caught here even if the file still compiles.
+	[TestMethod]
+	[DataRow("\"foo\"", "“foo”")] // ASCII " between non-letters → OpenQuote U+201C / CloseQuote U+201D
+	[DataRow("\"a\"b\"", "“a＂b”")] // ASCII " surrounded by letters on both sides → OtherQuote U+FF02
+	public void DefaultPreset_UsesUnicodeCurlyQuotesForOpenAndClose(string input, string expected)
+		=> Default.ReplaceFilenameChars(input).Should().Be(expected);
+}
+
 [TestClass]
 public class RemoveLastCharacter
 {