diff --git a/src/libs/utils/theme/theme.cpp b/src/libs/utils/theme/theme.cpp
index 41e7cb5a7bd..bbfd5c709d7 100644
--- a/src/libs/utils/theme/theme.cpp
+++ b/src/libs/utils/theme/theme.cpp
@@ -66,11 +66,11 @@ void setCreatorTheme(Theme *theme)
     m_creatorTheme = theme;
 }
 
-Theme::Theme(const QString &name, QObject *parent)
+Theme::Theme(const QString &id, QObject *parent)
   : QObject(parent)
   , d(new ThemePrivate)
 {
-    d->name = name;
+    d->id = id;
 }
 
 Theme::~Theme()
@@ -88,6 +88,11 @@ QStringList Theme::preferredStyles() const
     return d->preferredStyles;
 }
 
+QString Theme::id() const
+{
+    return d->id;
+}
+
 bool Theme::flag(Theme::Flag f) const
 {
     return d->flags[f];
@@ -130,14 +135,14 @@ QString Theme::filePath() const
     return d->fileName;
 }
 
-QString Theme::name() const
+QString Theme::displayName() const
 {
-    return d->name;
+    return d->displayName;
 }
 
-void Theme::setName(const QString &name)
+void Theme::setDisplayName(const QString &name)
 {
-    d->name = name;
+    d->displayName = name;
 }
 
 QVariantHash Theme::values() const
@@ -185,7 +190,7 @@ void Theme::writeSettings(const QString &filename) const
 
     const QMetaObject &m = *metaObject();
     {
-        settings.setValue(QLatin1String("ThemeName"), d->name);
+        settings.setValue(QLatin1String("ThemeName"), d->displayName);
         settings.setValue(QLatin1String("PreferredStyles"), d->preferredStyles);
     }
     {
@@ -264,7 +269,7 @@ void Theme::readSettings(QSettings &settings)
     const QMetaObject &m = *metaObject();
 
     {
-        d->name = settings.value(QLatin1String("ThemeName"), QLatin1String("unnamed")).toString();
+        d->displayName = settings.value(QLatin1String("ThemeName"), QLatin1String("unnamed")).toString();
         d->preferredStyles = settings.value(QLatin1String("PreferredStyles")).toStringList();
         d->preferredStyles.removeAll(QLatin1String(""));
     }
diff --git a/src/libs/utils/theme/theme.h b/src/libs/utils/theme/theme.h
index 525c2a0a33c..12c635e03ba 100644
--- a/src/libs/utils/theme/theme.h
+++ b/src/libs/utils/theme/theme.h
@@ -54,7 +54,7 @@ class QTCREATOR_UTILS_EXPORT Theme : public QObject
     Q_ENUMS(WidgetStyle)
 
 public:
-    Theme(const QString &name, QObject *parent = 0);
+    Theme(const QString &id, QObject *parent = 0);
     ~Theme();
 
     enum Color {
@@ -253,9 +253,10 @@ public:
     QPalette palette() const;
     QStringList preferredStyles() const;
 
+    QString id() const;
     QString filePath() const;
-    QString name() const;
-    void setName(const QString &name);
+    QString displayName() const;
+    void setDisplayName(const QString &displayName);
 
     QVariantHash values() const;
 
diff --git a/src/libs/utils/theme/theme_p.h b/src/libs/utils/theme/theme_p.h
index 22dcc44fb71..ea8b4d3d477 100644
--- a/src/libs/utils/theme/theme_p.h
+++ b/src/libs/utils/theme/theme_p.h
@@ -44,8 +44,9 @@ class QTCREATOR_UTILS_EXPORT ThemePrivate
 public:
     ThemePrivate();
 
+    QString id;
     QString fileName;
-    QString name;
+    QString displayName;
     QStringList preferredStyles;
     QVector<QPair<QColor, QString> > colors;
     QVector<QString> imageFiles;
diff --git a/src/plugins/coreplugin/coreplugin.cpp b/src/plugins/coreplugin/coreplugin.cpp
index f52fd828492..a2e62bc7d26 100644
--- a/src/plugins/coreplugin/coreplugin.cpp
+++ b/src/plugins/coreplugin/coreplugin.cpp
@@ -37,6 +37,7 @@
 #include "modemanager.h"
 #include "infobar.h"
 #include "iwizardfactory.h"
+#include "themesettings.h"
 
 #include <coreplugin/actionmanager/actionmanager.h>
 #include <coreplugin/documentmanager.h>
@@ -48,6 +49,7 @@
 
 #include <extensionsystem/pluginerroroverview.h>
 #include <extensionsystem/pluginmanager.h>
+#include <utils/algorithm.h>
 #include <utils/pathchooser.h>
 #include <utils/macroexpander.h>
 #include <utils/savefile.h>
@@ -58,7 +60,6 @@
 #include <QtPlugin>
 #include <QDebug>
 #include <QDateTime>
-#include <QDir>
 #include <QMenu>
 
 using namespace Core;
@@ -97,36 +98,11 @@ CorePlugin::~CorePlugin()
     setCreatorTheme(0);
 }
 
-static QString absoluteThemePath(const QString &themeName, bool userProvidedTheme)
-{
-    if (themeName.isEmpty())
-        return themeName;
-    QString res = QDir::fromNativeSeparators(themeName);
-    QFileInfo fi(res);
-    bool tryRawName = userProvidedTheme || fi.isAbsolute();
-    // Try the given name
-    if (tryRawName && fi.exists())
-        return fi.absoluteFilePath();
-    const QString suffix = QLatin1String("creatortheme");
-    // Try name.creatortheme
-    if (fi.suffix() != suffix) {
-        res = themeName + QLatin1Char('.') + suffix;
-        fi.setFile(res);
-        if (tryRawName && fi.exists())
-            return fi.absoluteFilePath();
-    }
-    if (fi.path().isEmpty())
-        return QString(); // absolute/relative path, but not found
-    // If only name was given, look it up in qtcreator/themes
-    res.prepend(ICore::resourcePath() + QLatin1String("/themes/"));
-    return QFileInfo::exists(res) ? res : QString();
-}
-
 void CorePlugin::parseArguments(const QStringList &arguments)
 {
-    const QString defaultTheme = QLatin1String("default");
-    QString themeName = ICore::settings()->value(
-                QLatin1String(Constants::SETTINGS_THEME), defaultTheme).toString();
+    const Id settingsThemeId = Id::fromSetting(ICore::settings()->value(
+                QLatin1String(Constants::SETTINGS_THEME), QLatin1String("default")));
+    Id themeId = settingsThemeId;
     QColor overrideColor;
     bool presentationMode = false;
     bool userProvidedTheme = false;
@@ -140,28 +116,28 @@ void CorePlugin::parseArguments(const QStringList &arguments)
         if (arguments.at(i) == QLatin1String("-presentationMode"))
             presentationMode = true;
         if (arguments.at(i) == QLatin1String("-theme")) {
-            themeName = arguments.at(i + 1);
+            themeId = Id::fromString(arguments.at(i + 1));
             userProvidedTheme = true;
             i++;
         }
     }
-
-    QString themeURI = absoluteThemePath(themeName, userProvidedTheme);
-    if (themeURI.isEmpty()) {
-        themeName = defaultTheme;
-        themeURI = QStringLiteral("%1/themes/%2.creatortheme").arg(ICore::resourcePath()).arg(themeName);
-        if (themeURI.isEmpty()) {
-            qCritical("%s", qPrintable(QCoreApplication::translate("Application", "No valid theme \"%1\"")
-                                       .arg(themeName)));
-        }
+    const QList<ThemeEntry> availableThemes = ThemeSettings::availableThemes();
+    int themeIndex = Utils::indexOf(availableThemes, Utils::equal(&ThemeEntry::id, themeId));
+    if (themeIndex < 0) {
+        themeIndex = Utils::indexOf(availableThemes,
+                                    Utils::equal(&ThemeEntry::id, settingsThemeId));
+    }
+    if (themeIndex < 0)
+        themeIndex = 0;
+    if (themeIndex < availableThemes.size()) {
+        const ThemeEntry themeEntry = availableThemes.at(themeIndex);
+        QSettings themeSettings(themeEntry.filePath(), QSettings::IniFormat);
+        Theme *theme = new Theme(themeEntry.id().toString(), qApp);
+        theme->readSettings(themeSettings);
+        if (theme->flag(Theme::ApplyThemePaletteGlobally))
+            QApplication::setPalette(theme->palette());
+        setCreatorTheme(theme);
     }
-
-    QSettings themeSettings(themeURI, QSettings::IniFormat);
-    Theme *theme = new Theme(themeName, qApp);
-    theme->readSettings(themeSettings);
-    if (theme->flag(Theme::ApplyThemePaletteGlobally))
-        QApplication::setPalette(theme->palette());
-    setCreatorTheme(theme);
 
     // defer creation of these widgets until here,
     // because they need a valid theme set
@@ -176,6 +152,10 @@ void CorePlugin::parseArguments(const QStringList &arguments)
 
 bool CorePlugin::initialize(const QStringList &arguments, QString *errorMessage)
 {
+    if (ThemeSettings::availableThemes().isEmpty()) {
+        *errorMessage = tr("No themes found in installation.");
+        return false;
+    }
     new ActionManager(this);
     Theme::initialPalette(); // Initialize palette before setting it
     qsrand(QDateTime::currentDateTime().toTime_t());
diff --git a/src/plugins/coreplugin/themeeditor/themesettingstablemodel.cpp b/src/plugins/coreplugin/themeeditor/themesettingstablemodel.cpp
index 13a2accda8a..c693fb304aa 100644
--- a/src/plugins/coreplugin/themeeditor/themesettingstablemodel.cpp
+++ b/src/plugins/coreplugin/themeeditor/themesettingstablemodel.cpp
@@ -222,7 +222,7 @@ void ThemeSettingsTableModel::initFrom(Theme *theme)
     }
 
     m_widgetStyle = theme->widgetStyle();
-    m_name = theme->d->name;
+    m_displayName = theme->d->displayName;
     m_preferredStyles = theme->d->preferredStyles;
 }
 
@@ -252,7 +252,7 @@ void ThemeSettingsTableModel::toTheme(Theme *t) const
     }
 
     theme->widgetStyle = m_widgetStyle;
-    theme->name = m_name;
+    theme->displayName = m_displayName;
     theme->preferredStyles = m_preferredStyles;
 }
 
diff --git a/src/plugins/coreplugin/themeeditor/themesettingstablemodel.h b/src/plugins/coreplugin/themeeditor/themesettingstablemodel.h
index 63a79947293..013d5a6d517 100644
--- a/src/plugins/coreplugin/themeeditor/themesettingstablemodel.h
+++ b/src/plugins/coreplugin/themeeditor/themesettingstablemodel.h
@@ -76,7 +76,7 @@ public:
     void initFrom(Utils::Theme *theme);
     void toTheme(Utils::Theme *theme) const;
 
-    QString m_name;
+    QString m_displayName;
     QStringList m_preferredStyles;
 
 public:
diff --git a/src/plugins/coreplugin/themesettings.cpp b/src/plugins/coreplugin/themesettings.cpp
index 4bad6936729..8f9f00a5285 100644
--- a/src/plugins/coreplugin/themesettings.cpp
+++ b/src/plugins/coreplugin/themesettings.cpp
@@ -31,14 +31,55 @@
 #include "themesettings.h"
 #include "themesettingswidget.h"
 #include "coreconstants.h"
+#include "icore.h"
+
+#include <utils/algorithm.h>
 
 #include <QCoreApplication>
+#include <QDebug>
+#include <QDir>
+#include <QSettings>
+
+static const char themeNameKey[] = "ThemeName";
 
 namespace Core {
 namespace Internal {
 
-ThemeSettings::ThemeSettings() :
-    m_widget(0)
+ThemeEntry::ThemeEntry(Id id, const QString &filePath, bool readOnly)
+    : m_id(id),
+      m_filePath(filePath),
+      m_readOnly(readOnly)
+{
+}
+
+Id ThemeEntry::id() const
+{
+    return m_id;
+}
+
+QString ThemeEntry::displayName() const
+{
+    if (m_displayName.isEmpty() && !m_filePath.isEmpty()) {
+        QSettings settings(m_filePath, QSettings::IniFormat);
+        m_displayName = settings.value(QLatin1String(themeNameKey),
+                                       QCoreApplication::tr("unnamed")).toString();
+        if (false) // TODO: Revert to m_readOnly
+            m_displayName = QCoreApplication::tr("%1 (built-in)").arg(m_displayName);
+    }
+    return m_displayName;
+}
+
+QString ThemeEntry::filePath() const
+{
+    return m_filePath;
+}
+
+bool ThemeEntry::readOnly() const
+{
+    return m_readOnly;
+}
+
+ThemeSettings::ThemeSettings()
 {
     setId(Constants::SETTINGS_ID_INTERFACE);
     setDisplayName(tr("Theme"));
@@ -71,5 +112,38 @@ void ThemeSettings::finish()
     m_widget = 0;
 }
 
+static void addThemesFromPath(const QString &path, bool readOnly, QList<ThemeEntry> *themes)
+{
+    static const QLatin1String extension(".creatortheme");
+    QDir themeDir(path);
+    themeDir.setNameFilters(QStringList() << QLatin1String("*.creatortheme"));
+    themeDir.setFilter(QDir::Files);
+    const QStringList themeList = themeDir.entryList();
+    foreach (const QString &fileName, themeList) {
+        QString id = QFileInfo(fileName).completeBaseName();
+        themes->append(ThemeEntry(Id::fromString(id), themeDir.absoluteFilePath(fileName), readOnly));
+    }
+}
+
+QList<ThemeEntry> ThemeSettings::availableThemes()
+{
+    QList<ThemeEntry> themes;
+
+    static const QString installThemeDir = ICore::resourcePath() + QLatin1String("/themes");
+    static const QString userThemeDir = ICore::userResourcePath() + QLatin1String("/themes");
+    addThemesFromPath(installThemeDir, /*readOnly=*/true, &themes);
+    if (themes.isEmpty())
+        qWarning() << "Warning: No themes found in installation: "
+                   << QDir::toNativeSeparators(installThemeDir);
+    // move default theme to front
+    int defaultIndex = Utils::indexOf(themes, Utils::equal(&ThemeEntry::id, Id("default")));
+    if (defaultIndex > 0) { // == exists and not at front
+        ThemeEntry defaultEntry = themes.takeAt(defaultIndex);
+        themes.prepend(defaultEntry);
+    }
+    addThemesFromPath(userThemeDir, /*readOnly=*/false, &themes);
+    return themes;
+}
+
 } // namespace Internal
 } // namespace Core
diff --git a/src/plugins/coreplugin/themesettings.h b/src/plugins/coreplugin/themesettings.h
index 415617b69bc..617dd74e676 100644
--- a/src/plugins/coreplugin/themesettings.h
+++ b/src/plugins/coreplugin/themesettings.h
@@ -31,6 +31,8 @@
 #ifndef THEMESETTINGS_H
 #define THEMESETTINGS_H
 
+#include "id.h"
+
 #include <coreplugin/dialogs/ioptionspage.h>
 
 namespace Core {
@@ -38,6 +40,24 @@ namespace Internal {
 
 class ThemeSettingsWidget;
 
+class ThemeEntry
+{
+public:
+    ThemeEntry() = default;
+    ThemeEntry(Id id, const QString &filePath, bool readOnly);
+
+    Id id() const;
+    QString displayName() const;
+    QString filePath() const;
+    bool readOnly() const;
+
+private:
+    Id m_id;
+    QString m_filePath;
+    mutable QString m_displayName;
+    bool m_readOnly = true;
+};
+
 class ThemeSettings : public IOptionsPage
 {
     Q_OBJECT
@@ -50,7 +70,9 @@ public:
     void apply();
     void finish();
 
-    ThemeSettingsWidget *m_widget;
+    static QList<ThemeEntry> availableThemes();
+private:
+    ThemeSettingsWidget *m_widget = 0;
 };
 
 } // namespace Internal
diff --git a/src/plugins/coreplugin/themesettingswidget.cpp b/src/plugins/coreplugin/themesettingswidget.cpp
index f098762dc24..7bd14a2c113 100644
--- a/src/plugins/coreplugin/themesettingswidget.cpp
+++ b/src/plugins/coreplugin/themesettingswidget.cpp
@@ -33,7 +33,9 @@
 #include "icore.h"
 #include "manhattanstyle.h"
 #include "themeeditor/themesettingstablemodel.h"
+#include "themesettings.h"
 
+#include <utils/algorithm.h>
 #include <utils/theme/theme.h>
 #include <utils/theme/theme_p.h>
 #include <utils/qtcassert.h>
@@ -52,8 +54,6 @@ using namespace Utils;
 namespace Core {
 namespace Internal {
 
-const char themeNameKey[] = "ThemeName";
-
 static QString customThemesPath()
 {
     return ICore::userResourcePath() + QLatin1String("/themes/");
@@ -81,42 +81,6 @@ static QString createThemeFileName(const QString &pattern)
     return fileName;
 }
 
-
-struct ThemeEntry
-{
-    ThemeEntry() : m_readOnly(true) {}
-    ThemeEntry(const QString &name, const QString &filePath, bool readOnly):
-        m_name(name),
-        m_filePath(filePath),
-        m_readOnly(readOnly)
-    {
-    }
-
-    QString name() const { return m_name; }
-    QString displayName() const;
-    QString filePath() const { return m_filePath; }
-    bool readOnly() const { return m_readOnly; }
-
-private:
-    QString m_name;
-    QString m_filePath;
-    mutable QString m_displayName;
-    bool m_readOnly;
-};
-
-QString ThemeEntry::displayName() const
-{
-    if (m_displayName.isEmpty()) {
-        QSettings settings(filePath(), QSettings::IniFormat);
-        m_displayName = settings.value(QLatin1String(themeNameKey),
-                                       QCoreApplication::tr("unnamed")).toString();
-        if (false) // TODO: Revert to m_readOnly
-            m_displayName = QCoreApplication::tr("%1 (built-in)").arg(m_displayName);
-    }
-    return m_displayName;
-}
-
-
 class ThemeListModel : public QAbstractListModel
 {
 public:
@@ -179,7 +143,7 @@ ThemeSettingsPrivate::ThemeSettingsPrivate(QWidget *widget)
     , m_refreshingThemeList(false)
     , m_ui(new Ui::ThemeSettings)
 {
-    m_currentTheme = ThemeEntry(creatorTheme()->name(), creatorTheme()->filePath(), true);
+    m_currentTheme = ThemeEntry(Id::fromString(creatorTheme()->id()), creatorTheme()->filePath(), true);
     m_ui->setupUi(widget);
     // TODO: Restore the editor and the buttons after improving the editor
     m_ui->editor->hide();
@@ -216,44 +180,15 @@ ThemeSettingsWidget::~ThemeSettingsWidget()
 
 void ThemeSettingsWidget::refreshThemeList()
 {
-    QList<ThemeEntry> themes;
-
-    QDir themeDir(ICore::resourcePath() + QLatin1String("/themes"));
-    themeDir.setNameFilters(QStringList() << QLatin1String("*.creatortheme"));
-    themeDir.setFilter(QDir::Files);
-
-    int selected = 0;
-
-    QStringList themeList = themeDir.entryList();
-    const QString defaultTheme = QLatin1String("default.creatortheme");
-    if (themeList.removeOne(defaultTheme))
-        themeList.prepend(defaultTheme);
-    const QLatin1String extension(".creatortheme");
-    for (int i = 0, total = themeList.count(); i < total; ++i) {
-        const QString fileName = themeList.at(i);
-        if (d->m_currentTheme.name() + extension == fileName)
-            selected = i;
-        QString name = fileName;
-        name.remove(extension);
-        themes.append(ThemeEntry(name, themeDir.absoluteFilePath(fileName), true));
-    }
-
-    if (themes.isEmpty())
-        qWarning() << "Warning: no themes found in path:" << themeDir.path();
-
-    themeDir.setPath(customThemesPath());
-    foreach (const QString &file, themeDir.entryList()) {
-        const QString fileName = themeDir.absoluteFilePath(file);
-        if (d->m_currentTheme.name() == fileName)
-            selected = themes.size();
-        themes.append(ThemeEntry(fileName, fileName, false));
-    }
-
-    d->m_currentTheme = themes[selected];
+    const QList<ThemeEntry> themes = ThemeSettings::availableThemes();
+    const int selected = Utils::indexOf(themes, Utils::equal(&ThemeEntry::id, d->m_currentTheme.id()));
 
     d->m_refreshingThemeList = true;
     d->m_themeListModel->setThemes(themes);
-    d->m_ui->themeComboBox->setCurrentIndex(selected);
+    if (selected >= 0) {
+        d->m_currentTheme = themes[selected];
+        d->m_ui->themeComboBox->setCurrentIndex(selected);
+    }
     d->m_refreshingThemeList = false;
 }
 
@@ -270,7 +205,7 @@ void ThemeSettingsWidget::themeSelected(int index)
         d->m_currentTheme = entry;
 
         QSettings settings(entry.filePath(), QSettings::IniFormat);
-        Theme theme(entry.name());
+        Theme theme(entry.id().toString());
         theme.readSettings(settings);
         d->m_ui->editor->initFrom(&theme);
     }
@@ -354,7 +289,7 @@ void ThemeSettingsWidget::maybeSaveTheme()
     messageBox->setDefaultButton(QMessageBox::Save);
 
     if (messageBox->exec() == QMessageBox::Save) {
-        Theme newTheme(d->m_currentTheme.name());
+        Theme newTheme(d->m_currentTheme.id().toString());
         d->m_ui->editor->model()->toTheme(&newTheme);
         newTheme.writeSettings(d->m_currentTheme.filePath());
     }
@@ -373,7 +308,7 @@ void ThemeSettingsWidget::renameTheme()
     dialog->setInputMode(QInputDialog::TextInput);
     dialog->setWindowTitle(tr("Rename Theme"));
     dialog->setLabelText(tr("Theme name:"));
-    dialog->setTextValue(d->m_ui->editor->model()->m_name);
+    dialog->setTextValue(d->m_ui->editor->model()->m_displayName);
     int ret = dialog->exec();
     QString newName = dialog->textValue();
     delete dialog;
@@ -382,9 +317,9 @@ void ThemeSettingsWidget::renameTheme()
         return;
 
     // overwrite file with new name
-    Theme newTheme(entry.name());
+    Theme newTheme(entry.id().toString());
     d->m_ui->editor->model()->toTheme(&newTheme);
-    newTheme.setName(newName);
+    newTheme.setDisplayName(newName);
     newTheme.writeSettings(entry.filePath());
 
     refreshThemeList();
@@ -401,8 +336,9 @@ void ThemeSettingsWidget::copyThemeByName(const QString &name)
     QString baseFileName = QFileInfo(entry.filePath()).completeBaseName();
     baseFileName += QLatin1String("_copy%1.creatortheme");
     QString fileName = createThemeFileName(baseFileName);
+    QString id = QFileInfo(fileName).completeBaseName();
 
-    if (fileName.isEmpty())
+    if (fileName.isEmpty() || id.isEmpty())
         return;
 
     // Ask about saving any existing modifactions
@@ -410,18 +346,18 @@ void ThemeSettingsWidget::copyThemeByName(const QString &name)
 
     Theme newTheme(fileName);
     d->m_ui->editor->model()->toTheme(&newTheme);
-    newTheme.setName(name);
+    newTheme.setDisplayName(name);
     newTheme.writeSettings(fileName);
 
-    d->m_currentTheme = ThemeEntry(fileName, fileName, true);
+    d->m_currentTheme = ThemeEntry(Id::fromString(id), fileName, true);
 
     refreshThemeList();
 }
 
 void ThemeSettingsWidget::apply()
 {
-    const QString themeName = d->m_currentTheme.name();
-    Theme *newTheme = new Theme(themeName);
+    const QString themeId = d->m_currentTheme.id().toString();
+    Theme *newTheme = new Theme(themeId);
     if (d->m_currentTheme.readOnly()) {
         QSettings themeSettings(d->m_currentTheme.filePath(), QSettings::IniFormat);
         newTheme->readSettings(themeSettings);
@@ -447,7 +383,7 @@ void ThemeSettingsWidget::apply()
 
     // save filename of selected theme in global config
     QSettings *settings = ICore::settings();
-    settings->setValue(QLatin1String(Constants::SETTINGS_THEME), themeName);
+    settings->setValue(QLatin1String(Constants::SETTINGS_THEME), themeId);
 }
 
 } // namespace Internal