diff --git a/app/src/main/java/eu/faircode/email/UnknownCharsetProvider.java b/app/src/main/java/eu/faircode/email/UnknownCharsetProvider.java
index b2c0a09740..1fcba6c4cf 100644
--- a/app/src/main/java/eu/faircode/email/UnknownCharsetProvider.java
+++ b/app/src/main/java/eu/faircode/email/UnknownCharsetProvider.java
@@ -20,6 +20,7 @@ import android.text.TextUtils;
 import java.nio.charset.Charset;
 import java.nio.charset.StandardCharsets;
 import java.nio.charset.spi.CharsetProvider;
+import java.text.Normalizer;
 import java.util.Collections;
 import java.util.Iterator;
 
@@ -56,6 +57,10 @@ public class UnknownCharsetProvider extends CharsetProvider {
 
             name = name.replace("\"", "");
 
+            // WİNDOWS-1254
+            name = Normalizer.normalize(name, Normalizer.Form.NFKD)
+                    .replaceAll("[^\\p{ASCII}]", "");
+
             int sp = name.indexOf(" ");
             if (sp > 0)
                 name = name.substring(0, sp);