diff --git a/src/emu/debug/debugcpu.cpp b/src/emu/debug/debugcpu.cpp
index 60c41c0b5ee..eab6f7771e7 100644
--- a/src/emu/debug/debugcpu.cpp
+++ b/src/emu/debug/debugcpu.cpp
@@ -49,6 +49,7 @@ debugger_cpu::debugger_cpu(running_machine &machine)
 	, m_breakcpu(nullptr)
 	, m_symtable(nullptr)
 	, m_execution_state(EXECUTION_STATE_STOPPED)
+	, m_stop_when_not_device(nullptr)
 	, m_bpindex(1)
 	, m_wpindex(1)
 	, m_rpindex(1)