diff --git a/components/lazdebuggers/lazdebuggerfp/fpdebugdebugger.pas b/components/lazdebuggers/lazdebuggerfp/fpdebugdebugger.pas
index 23ed1e79d5..d72ded7648 100644
--- a/components/lazdebuggers/lazdebuggerfp/fpdebugdebugger.pas
+++ b/components/lazdebuggers/lazdebuggerfp/fpdebugdebugger.pas
@@ -779,7 +779,7 @@ begin
   FCallstack := ACallstack;
   FCallstack.AddFreeNotification(@DoCallstackFreed_DecRef);
   if not ADebugger.FDbgController.CurrentProcess.GetThread(FCallstack.ThreadId, AThread) then
-    ARequiredMinCount := -1;  // error
+    ARequiredMinCount := -2;  // error
   inherited Create(ADebugger, ARequiredMinCount, AThread);
 end;
 
diff --git a/components/lazdebuggers/lazdebuggerfp/fpdebugdebuggerworkthreads.pas b/components/lazdebuggers/lazdebuggerfp/fpdebugdebuggerworkthreads.pas
index 88274ff7db..89812f5231 100644
--- a/components/lazdebuggers/lazdebuggerfp/fpdebugdebuggerworkthreads.pas
+++ b/components/lazdebuggers/lazdebuggerfp/fpdebugdebuggerworkthreads.pas
@@ -564,7 +564,7 @@ procedure TFpThreadWorkerPrepareCallStackEntryList.DoExecute;
 var
   t: TDbgThread;
 begin
-  if FRequiredMinCount < 0 then
+  if FRequiredMinCount < -1 then
     exit;
   if FThread = nil then begin
     for t in FDebugger.FDbgController.CurrentProcess.ThreadMap do begin