diff --git a/src/Gui/DlgCreateNewPreferencePackImp.cpp b/src/Gui/DlgCreateNewPreferencePackImp.cpp
index 498199f7b6..94af8a73f7 100644
--- a/src/Gui/DlgCreateNewPreferencePackImp.cpp
+++ b/src/Gui/DlgCreateNewPreferencePackImp.cpp
@@ -94,6 +94,11 @@ void DlgCreateNewPreferencePackImp::setPreferencePackTemplates(const std::vector
     }
 }
 
+void Gui::Dialog::DlgCreateNewPreferencePackImp::setPreferencePackNames(const std::vector<std::string>& usedNames)
+{
+    _existingPackNames = usedNames;
+}
+
 std::vector<Gui::PreferencePackManager::TemplateFile> DlgCreateNewPreferencePackImp::selectedTemplates() const
 {
     std::vector<Gui::PreferencePackManager::TemplateFile> results;
@@ -149,5 +154,19 @@ void DlgCreateNewPreferencePackImp::on_lineEdit_textEdited(const QString& text)
     ui->buttonBox->button(QDialogButtonBox::Ok)->setDisabled(text.isEmpty());
 }
 
+void Gui::Dialog::DlgCreateNewPreferencePackImp::accept()
+{
+    // Ensure that the chosen name is either unique, or that the user actually wants to overwrite the old one
+    if (auto chosenName = ui->lineEdit->text().toStdString();
+        std::find(_existingPackNames.begin(), _existingPackNames.end(), chosenName) != _existingPackNames.end()) {
+        auto result = QMessageBox::warning(this, tr("Pack already exists"), 
+                                           tr("A preference pack with that name already exists. Do you want to overwrite it?"),
+                                           QMessageBox::Yes | QMessageBox::Cancel);
+        if (result == QMessageBox::Cancel)
+            return;
+    }
+    QDialog::accept();
+}
+
 
 #include "moc_DlgCreateNewPreferencePackImp.cpp"
diff --git a/src/Gui/DlgCreateNewPreferencePackImp.h b/src/Gui/DlgCreateNewPreferencePackImp.h
index 6e4f75058b..b6d0caf705 100644
--- a/src/Gui/DlgCreateNewPreferencePackImp.h
+++ b/src/Gui/DlgCreateNewPreferencePackImp.h
@@ -55,6 +55,7 @@ public:
     ~DlgCreateNewPreferencePackImp();
 
     void setPreferencePackTemplates(const std::vector<PreferencePackManager::TemplateFile> &availableTemplates);
+    void setPreferencePackNames(const std::vector<std::string>& usedNames);
 
     std::vector<PreferencePackManager::TemplateFile> selectedTemplates() const;
     std::string preferencePackName() const;
@@ -65,11 +66,14 @@ protected Q_SLOTS:
 
     void on_lineEdit_textEdited(const QString &text);
 
+    void accept() override;
+
 private:
     std::unique_ptr<Ui_DlgCreateNewPreferencePack> ui;
     std::map<std::string, QTreeWidgetItem*> _groups;
     std::vector<PreferencePackManager::TemplateFile> _templates;
     QRegExpValidator _nameValidator;
+    std::vector<std::string> _existingPackNames;
 };
 
 } // namespace Dialog
diff --git a/src/Gui/DlgGeneralImp.cpp b/src/Gui/DlgGeneralImp.cpp
index b4bd12ebea..6f7fc277b9 100644
--- a/src/Gui/DlgGeneralImp.cpp
+++ b/src/Gui/DlgGeneralImp.cpp
@@ -359,8 +359,15 @@ void DlgGeneralImp::preferencePackSelectionChanged()
 void DlgGeneralImp::saveAsNewPreferencePack()
 {
     // Create and run a modal New PreferencePack dialog box
+    auto appearancePacks = Application::Instance->prefPackManager()->preferencePackNames(PreferencePack::Type::Appearance);
+    auto behaviorPacks = Application::Instance->prefPackManager()->preferencePackNames(PreferencePack::Type::Behavior);
+    auto combinationPacks = Application::Instance->prefPackManager()->preferencePackNames(PreferencePack::Type::Combination);
+    auto allPacks = appearancePacks;
+    allPacks.insert(allPacks.end(), behaviorPacks.begin(), behaviorPacks.end());
+    allPacks.insert(allPacks.end(), combinationPacks.begin(), combinationPacks.end());
     newPreferencePackDialog = std::make_unique<DlgCreateNewPreferencePackImp>(this);
     newPreferencePackDialog->setPreferencePackTemplates(Application::Instance->prefPackManager()->templateFiles());
+    newPreferencePackDialog->setPreferencePackNames(allPacks);
     connect(newPreferencePackDialog.get(), &DlgCreateNewPreferencePackImp::accepted, this, &DlgGeneralImp::newPreferencePackDialogAccepted);
     newPreferencePackDialog->open();
 }