diff --git a/tools/cabana/dbc/dbcfile.cc b/tools/cabana/dbc/dbcfile.cc
index 8b4f98508c..c4025725ac 100644
--- a/tools/cabana/dbc/dbcfile.cc
+++ b/tools/cabana/dbc/dbcfile.cc
@@ -186,6 +186,19 @@ QStringList DBCFile::signalNames() const {
   return ret;
 }
 
+int DBCFile::signalCount(const MessageId &id) const {
+  if (msgs.count(id.address) == 0) return 0;
+  return msgs.at(id.address).sigs.size();
+}
+
+int DBCFile::signalCount() const {
+  int total = 0;
+  for (auto const& [_, msg] : msgs) {
+    total += msg.sigs.size();
+  }
+  return total;
+}
+
 int DBCFile::msgCount() const {
   return msgs.size();
 }
@@ -194,6 +207,10 @@ QString DBCFile::name() const {
   return name_;
 }
 
+bool DBCFile::isEmpty() const {
+  return (signalCount() == 0) && name().isEmpty();
+}
+
 void DBCFile::parseExtraInfo(const QString &content) {
   static QRegularExpression bo_regexp(R"(^BO_ (\w+) (\w+) *: (\w+) (\w+))");
   static QRegularExpression sg_regexp(R"(^SG_ (\w+) : (\d+)\|(\d+)@(\d+)([\+|\-]) \(([0-9.+\-eE]+),([0-9.+\-eE]+)\) \[([0-9.+\-eE]+)\|([0-9.+\-eE]+)\] \"(.*)\" (.*))");
diff --git a/tools/cabana/dbc/dbcfile.h b/tools/cabana/dbc/dbcfile.h
index 082ee773b1..96fbe6a9f1 100644
--- a/tools/cabana/dbc/dbcfile.h
+++ b/tools/cabana/dbc/dbcfile.h
@@ -43,8 +43,11 @@ public:
   const cabana::Msg *msg(uint32_t address) const;
   const cabana::Msg* msg(const QString &name);
   QStringList signalNames() const;
+  int signalCount(const MessageId &id) const;
+  int signalCount() const;
   int msgCount() const;
   QString name() const;
+  bool isEmpty() const;
 
   QString filename;
 
diff --git a/tools/cabana/dbc/dbcmanager.cc b/tools/cabana/dbc/dbcmanager.cc
index 24803a303f..123d783986 100644
--- a/tools/cabana/dbc/dbcmanager.cc
+++ b/tools/cabana/dbc/dbcmanager.cc
@@ -180,6 +180,26 @@ QStringList DBCManager::signalNames() const {
   return ret;
 }
 
+int DBCManager::signalCount(const MessageId &id) const {
+  auto sources_dbc_file = findDBCFile(id);
+  if (!sources_dbc_file) {
+    return 0;
+  }
+
+  auto [_, dbc_file] = *sources_dbc_file;
+  return dbc_file->signalCount(id);
+}
+
+int DBCManager::signalCount() const {
+  int ret = 0;
+
+  for (auto &[_, dbc_file] : dbc_files) {
+    ret += dbc_file->signalCount();
+  }
+
+  return ret;
+}
+
 int DBCManager::msgCount() const {
   int ret = 0;
 
@@ -194,6 +214,16 @@ int DBCManager::dbcCount() const {
   return dbc_files.size();
 }
 
+int DBCManager::nonEmptyDBCCount() const {
+  int cnt = 0;
+  for (auto &[_, dbc_file] : dbc_files) {
+    if (!dbc_file->isEmpty()) {
+      cnt++;
+    }
+  }
+  return cnt;
+}
+
 void DBCManager::updateSources(const SourceSet &s) {
   sources = s;
 }
diff --git a/tools/cabana/dbc/dbcmanager.h b/tools/cabana/dbc/dbcmanager.h
index f9af96516c..60d8a072ec 100644
--- a/tools/cabana/dbc/dbcmanager.h
+++ b/tools/cabana/dbc/dbcmanager.h
@@ -38,8 +38,11 @@ public:
   const cabana::Msg* msg(uint8_t source, const QString &name);
 
   QStringList signalNames() const;
+  int signalCount(const MessageId &id) const;
+  int signalCount() const;
   int msgCount() const;
   int dbcCount() const;
+  int nonEmptyDBCCount() const;
 
   std::optional<std::pair<SourceSet, DBCFile*>> findDBCFile(const uint8_t source) const;
   std::optional<std::pair<SourceSet, DBCFile*>> findDBCFile(const MessageId &id) const;
diff --git a/tools/cabana/mainwin.cc b/tools/cabana/mainwin.cc
index c979a20f16..5b6d436dca 100644
--- a/tools/cabana/mainwin.cc
+++ b/tools/cabana/mainwin.cc
@@ -232,6 +232,7 @@ void MainWindow::undoStackIndexChanged(int index) {
   prev_undostack_index = index;
   prev_undostack_count = count;
   autoSave();
+  updateLoadSaveMenus();
 }
 
 void MainWindow::undoStackCleanChanged(bool clean) {
@@ -411,7 +412,7 @@ void MainWindow::saveFile() {
     if (!dbc_file->filename.isEmpty()) {
       dbc_file->save();
       updateRecentFiles(dbc_file->filename);
-    } else {
+    } else if (!dbc_file->isEmpty()) {
       QString fn = QFileDialog::getSaveFileName(this, tr("Save File"), QDir::cleanPath(settings.last_dir + "/untitled.dbc"), tr("DBC (*.dbc)"));
       if (!fn.isEmpty()) {
         dbc_file->saveAs(fn);
@@ -426,22 +427,22 @@ void MainWindow::saveFile() {
 
 void MainWindow::saveAs() {
   // Assume only one file is open
-  assert(dbc()->dbcCount() > 0);
-  auto &[_, dbc_file] = dbc()->dbc_files.first();
-
-  QString fn = QFileDialog::getSaveFileName(this, tr("Save File"), QDir::cleanPath(settings.last_dir + "/untitled.dbc"), tr("DBC (*.dbc)"));
-  if (!fn.isEmpty()) {
-    dbc_file->saveAs(fn);
+  for (auto &[s, dbc_file] : dbc()->dbc_files) {
+    if (dbc_file->isEmpty()) continue;
+    QString fn = QFileDialog::getSaveFileName(this, tr("Save File"), QDir::cleanPath(settings.last_dir + "/untitled.dbc"), tr("DBC (*.dbc)"));
+    if (!fn.isEmpty()) {
+      dbc_file->saveAs(fn);
+    }
   }
 }
 
 void MainWindow::saveDBCToClipboard() {
   // Assume only one file is open
-  assert(dbc()->dbcCount() > 0);
-
-  auto &[_, dbc_file] = dbc()->dbc_files.first();
-  QGuiApplication::clipboard()->setText(dbc_file->generateDBC());
-  QMessageBox::information(this, tr("Copy To Clipboard"), tr("DBC Successfully copied!"));
+  for (auto &[s, dbc_file] : dbc()->dbc_files) {
+    if (dbc_file->isEmpty()) continue;
+    QGuiApplication::clipboard()->setText(dbc_file->generateDBC());
+    QMessageBox::information(this, tr("Copy To Clipboard"), tr("DBC Successfully copied!"));
+  }
 }
 
 void MainWindow::updateSources(const SourceSet &s) {
@@ -450,17 +451,20 @@ void MainWindow::updateSources(const SourceSet &s) {
 }
 
 void MainWindow::updateLoadSaveMenus() {
-  if (dbc()->dbcCount() > 1) {
+  int cnt = dbc()->nonEmptyDBCCount();
+  save_dbc->setEnabled(cnt > 0);
+
+  if (cnt > 1) {
     save_dbc->setText(tr("Save %1 DBCs...").arg(dbc()->dbcCount()));
   } else {
     save_dbc->setText(tr("Save DBC..."));
   }
 
   // TODO: Support save as for multiple files
-  save_dbc_as->setEnabled(dbc()->dbcCount() == 1);
+  save_dbc_as->setEnabled(cnt == 1);
 
   // TODO: Support clipboard for multiple files
-  copy_dbc_to_clipboard->setEnabled(dbc()->dbcCount() == 1);
+  copy_dbc_to_clipboard->setEnabled(cnt == 1);
 
 
   QList<uint8_t> sources_sorted = sources.toList();