diff --git a/Core/SaveState.cpp b/Core/SaveState.cpp
index 16779e73d6..0b62c55341 100644
--- a/Core/SaveState.cpp
+++ b/Core/SaveState.cpp
@@ -319,7 +319,7 @@ namespace SaveState
 			I18NCategory *s = GetI18NCategory("Screen");
 			osm.Show("Failed to load state. Error in the file system.", 2.0);
 			if (callback)
-				(*callback)(false, cbUserData);
+				callback(false, cbUserData);
 		}
 	}
 
@@ -327,12 +327,12 @@ namespace SaveState
 	{
 		std::string fn = GenerateSaveSlotFilename(slot, STATE_EXTENSION);
 		if (!fn.empty()) {
-			Save(fn, callback, cbUserData);
+			Save(fn + ".tmp", callback, cbUserData);
 		} else {
 			I18NCategory *s = GetI18NCategory("Screen");
 			osm.Show("Failed to save state. Error in the file system.", 2.0);
 			if (callback)
-				(*callback)(false, cbUserData);
+				callback(false, cbUserData);
 		}
 	}
 
diff --git a/Core/SaveState.h b/Core/SaveState.h
index 840c75fc66..856143c20a 100644
--- a/Core/SaveState.h
+++ b/Core/SaveState.h
@@ -18,11 +18,12 @@
 #include <string>
 #include <vector>
 
+#include "base/functional.h"
 #include "Common/ChunkFile.h"
 
 namespace SaveState
 {
-	typedef void (*Callback)(bool status, void *cbUserData);
+	typedef std::function<void(bool status, void *cbUserData)> Callback;
 
 	// TODO: Better place for this?
 	const int REVISION = 4;
@@ -44,22 +45,22 @@ namespace SaveState
 
 	// Load the specified file into the current state (async.)
 	// Warning: callback will be called on a different thread.
-	void Load(const std::string &filename, Callback callback = 0, void *cbUserData = 0);
+	void Load(const std::string &filename, Callback callback = nullptr, void *cbUserData = 0);
 
 	// Save the current state to the specified file (async.)
 	// Warning: callback will be called on a different thread.
-	void Save(const std::string &filename, Callback callback = 0, void *cbUserData = 0);
+	void Save(const std::string &filename, Callback callback = nullptr, void *cbUserData = 0);
 
 	CChunkFileReader::Error SaveToRam(std::vector<u8> &state);
 	CChunkFileReader::Error LoadFromRam(std::vector<u8> &state);
 
 	// For testing / automated tests.  Runs a save state verification pass (async.)
 	// Warning: callback will be called on a different thread.
-	void Verify(Callback callback = 0, void *cbUserData = 0);
+	void Verify(Callback callback = nullptr, void *cbUserData = 0);
 
 	// To go back to a previous snapshot (only if enabled.)
 	// Warning: callback will be called on a different thread.
-	void Rewind(Callback callback = 0, void *cbUserData = 0);
+	void Rewind(Callback callback = nullptr, void *cbUserData = 0);
 
 	// Returns true if there are rewind snapshots available.
 	bool CanRewind();
diff --git a/UI/EmuScreen.cpp b/UI/EmuScreen.cpp
index 4bdf350781..e72aea920d 100644
--- a/UI/EmuScreen.cpp
+++ b/UI/EmuScreen.cpp
@@ -332,11 +332,11 @@ void EmuScreen::onVKeyDown(int virtualKeyCode) {
 		}
 		break;
 	case VIRTKEY_SAVE_STATE:
-		SaveState::SaveSlot(g_Config.iCurrentStateSlot, 0);
+		SaveState::SaveSlot(g_Config.iCurrentStateSlot, nullptr);
 		break;
 	case VIRTKEY_LOAD_STATE:
 		if (SaveState::HasSaveInSlot(g_Config.iCurrentStateSlot)) {
-			SaveState::LoadSlot(g_Config.iCurrentStateSlot, 0);
+			SaveState::LoadSlot(g_Config.iCurrentStateSlot, nullptr);
 		}
 		break;
 	case VIRTKEY_NEXT_SLOT:
@@ -800,7 +800,7 @@ void EmuScreen::autoLoad() {
 	//check if save state has save, if so, load
 	int lastSlot = SaveState::GetNewestSlot();
 	if (g_Config.bEnableAutoLoad && lastSlot != -1) {
-		SaveState::LoadSlot(lastSlot, 0, 0);
+		SaveState::LoadSlot(lastSlot, nullptr, 0);
 		g_Config.iCurrentStateSlot = lastSlot;
 	}
 }
diff --git a/UI/MainScreen.cpp b/UI/MainScreen.cpp
index 28af8c37b6..c109ad1c50 100644
--- a/UI/MainScreen.cpp
+++ b/UI/MainScreen.cpp
@@ -1235,21 +1235,21 @@ UI::EventReturn GamePauseScreen::OnReportFeedback(UI::EventParams &e) {
 }
 
 UI::EventReturn GamePauseScreen::OnLoadState(UI::EventParams &e) {
-	SaveState::LoadSlot(saveSlots_->GetSelection(), 0, 0);
+	SaveState::LoadSlot(saveSlots_->GetSelection(), nullptr, 0);
 
 	screenManager()->finishDialog(this, DR_CANCEL);
 	return UI::EVENT_DONE;
 }
 
 UI::EventReturn GamePauseScreen::OnSaveState(UI::EventParams &e) {
-	SaveState::SaveSlot(saveSlots_->GetSelection(), 0, 0);
+	SaveState::SaveSlot(saveSlots_->GetSelection(), nullptr, 0);
 
 	screenManager()->finishDialog(this, DR_CANCEL);
 	return UI::EVENT_DONE;
 }
 
 UI::EventReturn GamePauseScreen::OnRewind(UI::EventParams &e) {
-	SaveState::Rewind(0, 0);
+	SaveState::Rewind(nullptr, 0);
 
 	screenManager()->finishDialog(this, DR_CANCEL);
 	return UI::EVENT_DONE;