diff --git a/src/plugins/debugger/debuggermanager.cpp b/src/plugins/debugger/debuggermanager.cpp
index 04875e12fd5d20c13047afac43d8753bd64ceec6..f696d728467654a5df68124e060c28f030c97fcc 100644
--- a/src/plugins/debugger/debuggermanager.cpp
+++ b/src/plugins/debugger/debuggermanager.cpp
@@ -791,6 +791,11 @@ bool DebuggerManager::startNewDebugger(StartMode mode)
         m_processArgs = QStringList();
         m_workingDir = QString();
         m_attachedPID = dlg.attachPID();
+        if (m_attachedPID == 0) {
+            QMessageBox::warning(mainWindow(), tr("Warning"),
+                tr("Cannot attach to PID 0"));
+            return false;
+        }
     } else if (startMode() == startInternal) {
         if (m_executable.isEmpty()) {
             QString startDirectory = m_executable;