diff --git a/launcher/LoggedProcess.cpp b/launcher/LoggedProcess.cpp
index fadd64e68..35ce4e0e5 100644
--- a/launcher/LoggedProcess.cpp
+++ b/launcher/LoggedProcess.cpp
@@ -39,7 +39,8 @@
 #include <QTextDecoder>
 #include "MessageLevel.h"
 
-LoggedProcess::LoggedProcess(QObject* parent) : QProcess(parent)
+LoggedProcess::LoggedProcess(const QTextCodec* output_codec, QObject* parent)
+    : QProcess(parent), m_err_decoder(output_codec), m_out_decoder(output_codec)
 {
     // QProcess has a strange interface... let's map a lot of those into a few.
     connect(this, &QProcess::readyReadStandardOutput, this, &LoggedProcess::on_stdOut);
diff --git a/launcher/LoggedProcess.h b/launcher/LoggedProcess.h
index 46bdaa830..75ba15dfd 100644
--- a/launcher/LoggedProcess.h
+++ b/launcher/LoggedProcess.h
@@ -49,7 +49,7 @@ class LoggedProcess : public QProcess {
     enum State { NotRunning, Starting, FailedToStart, Running, Finished, Crashed, Aborted };
 
    public:
-    explicit LoggedProcess(QObject* parent = 0);
+    explicit LoggedProcess(const QTextCodec* output_codec = QTextCodec::codecForLocale(), QObject* parent = 0);
     virtual ~LoggedProcess();
 
     State state() const;
@@ -80,8 +80,8 @@ class LoggedProcess : public QProcess {
     QStringList reprocess(const QByteArray& data, QTextDecoder& decoder);
 
    private:
-    QTextDecoder m_err_decoder = QTextDecoder(QTextCodec::codecForLocale());
-    QTextDecoder m_out_decoder = QTextDecoder(QTextCodec::codecForLocale());
+    QTextDecoder m_err_decoder;
+    QTextDecoder m_out_decoder;
     QString m_leftover_line;
     bool m_killed = false;
     State m_state = NotRunning;
diff --git a/launcher/java/JavaVersion.cpp b/launcher/java/JavaVersion.cpp
index 5e9700012..bca50f2c9 100644
--- a/launcher/java/JavaVersion.cpp
+++ b/launcher/java/JavaVersion.cpp
@@ -48,6 +48,12 @@ bool JavaVersion::requiresPermGen() const
     return !m_parseable || m_major < 8;
 }
 
+bool JavaVersion::defaultsToUtf8() const
+{
+    // starting from Java 18, UTF-8 is the default charset: https://openjdk.org/jeps/400
+    return m_parseable && m_major >= 18;
+}
+
 bool JavaVersion::isModular() const
 {
     return m_parseable && m_major >= 9;
diff --git a/launcher/java/JavaVersion.h b/launcher/java/JavaVersion.h
index dfb4770da..c070bdeec 100644
--- a/launcher/java/JavaVersion.h
+++ b/launcher/java/JavaVersion.h
@@ -25,7 +25,7 @@ class JavaVersion {
     bool operator>(const JavaVersion& rhs);
 
     bool requiresPermGen() const;
-
+    bool defaultsToUtf8() const;
     bool isModular() const;
 
     QString toString() const;
diff --git a/launcher/minecraft/launch/LauncherPartLaunch.cpp b/launcher/minecraft/launch/LauncherPartLaunch.cpp
index 10c14a95f..d9a2b9b6b 100644
--- a/launcher/minecraft/launch/LauncherPartLaunch.cpp
+++ b/launcher/minecraft/launch/LauncherPartLaunch.cpp
@@ -48,7 +48,9 @@
 #include "gamemode_client.h"
 #endif
 
-LauncherPartLaunch::LauncherPartLaunch(LaunchTask* parent) : LaunchStep(parent)
+LauncherPartLaunch::LauncherPartLaunch(LaunchTask* parent)
+    : LaunchStep(parent)
+    , m_process(parent->instance()->getJavaVersion().defaultsToUtf8() ? QTextCodec::codecForName("UTF-8") : QTextCodec::codecForLocale())
 {
     if (parent->instance()->settings()->get("CloseAfterLaunch").toBool()) {
         std::shared_ptr<QMetaObject::Connection> connection{ new QMetaObject::Connection };