diff --git a/SPID/CMakeLists.txt b/SPID/CMakeLists.txt
index df6aa8a..c33a6f2 100644
--- a/SPID/CMakeLists.txt
+++ b/SPID/CMakeLists.txt
@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.20)
 set(NAME "po3_SpellPerkItemDistributor" CACHE STRING "")
-set(VERSION 6.0.3 CACHE STRING "")
+set(VERSION 6.1.0 CACHE STRING "")
 set(AE_VERSION 1)
 set(VR_VERSION 1)
 
diff --git a/SPID/include/PCH.h b/SPID/include/PCH.h
index 5b7ebb7..3d06550 100644
--- a/SPID/include/PCH.h
+++ b/SPID/include/PCH.h
@@ -4,6 +4,7 @@
 #define NOMINMAX
 
 #include <ranges>
+#include <shared_mutex>
 
 #include "RE/Skyrim.h"
 #include "SKSE/SKSE.h"
diff --git a/SPID/include/PCLevelMultManager.h b/SPID/include/PCLevelMultManager.h
index fe849b3..3bf390d 100644
--- a/SPID/include/PCLevelMultManager.h
+++ b/SPID/include/PCLevelMultManager.h
@@ -78,9 +78,13 @@ namespace PCLevelMult
 			Map<std::uint16_t, Entries> entries{};  // Actor Level, Entries
 		};
 
-		Map<std::uint64_t,          // PlayerID
+		using Lock = std::shared_mutex;
+		using Locker = std::lock_guard<Lock>;
+
+	    Map<std::uint64_t,          // PlayerID
 			Map<RE::FormID, Data>>  // NPC formID, Data
-			cache{};
+			_cache{};
+		mutable Lock _lock;
 
 		std::uint64_t currentPlayerID{ 0 };
 		std::uint64_t oldPlayerID{ 0 };
diff --git a/SPID/src/PCLevelMultManager.cpp b/SPID/src/PCLevelMultManager.cpp
index 2467811..2da4baf 100644
--- a/SPID/src/PCLevelMultManager.cpp
+++ b/SPID/src/PCLevelMultManager.cpp
@@ -63,7 +63,8 @@ namespace PCLevelMult
 			return false;
 		}
 
-		if (const auto idIt = cache.find(a_input.playerID); idIt != cache.end()) {
+		Locker lock(_lock);
+	    if (const auto idIt = _cache.find(a_input.playerID); idIt != _cache.end()) {
 			auto& npcFormIDMap = idIt->second;
 			if (const auto npcIt = npcFormIDMap.find(a_input.npcFormID); npcIt != npcFormIDMap.end()) {
 				auto& [levelCapState, levelMap] = npcIt->second;
@@ -86,7 +87,8 @@ namespace PCLevelMult
 			return false;
 		}
 
-		return cache[a_input.playerID]
+		Locker lock(_lock);
+	    return _cache[a_input.playerID]
 		            [a_input.npcFormID]
 		                .entries[a_input.npcLevel]
 		                .rejectedEntries[a_distributedFormID]
@@ -96,7 +98,8 @@ namespace PCLevelMult
 
 	void Manager::DumpRejectedEntries()
 	{
-		for (auto& [playerID, npcFormIDs] : cache) {
+		Locker lock(_lock);
+	    for (auto& [playerID, npcFormIDs] : _cache) {
 			logger::info("PlayerID : {:X}", playerID);
 			for (auto& [npcFormID, levelMap] : npcFormIDs) {
 				logger::info("\tNPC : {} [{:X}]", Cache::EditorID::GetEditorID(npcFormID), npcFormID);
@@ -115,7 +118,8 @@ namespace PCLevelMult
 
 	bool Manager::FindDistributedEntry(const Input& a_input)
 	{
-		if (const auto it = cache.find(a_input.playerID); it != cache.end()) {
+		Locker lock(_lock);
+	    if (const auto it = _cache.find(a_input.playerID); it != _cache.end()) {
 			if (const auto npcIt = it->second.find(a_input.npcFormID); npcIt != it->second.end()) {
 				return !npcIt->second.entries.empty();
 			}
@@ -129,7 +133,8 @@ namespace PCLevelMult
 			return;
 		}
 
-		cache[a_input.playerID][a_input.npcFormID].entries[a_input.npcLevel].distributedEntries.push_back({ a_distributedFormID, a_idx });
+		Locker lock(_lock);
+	    _cache[a_input.playerID][a_input.npcFormID].entries[a_input.npcLevel].distributedEntries.push_back({ a_distributedFormID, a_idx });
 	}
 
 	void Manager::ForEachDistributedEntry(const Input& a_input, std::function<void(RE::TESForm&, IdxOrCount a_idx, bool)> a_fn) const
@@ -138,7 +143,8 @@ namespace PCLevelMult
 			return;
 		}
 
-		if (const auto idIt = cache.find(a_input.playerID); idIt != cache.end()) {
+		Locker lock(_lock);
+	    if (const auto idIt = _cache.find(a_input.playerID); idIt != _cache.end()) {
 			auto& npcFormIDMap = idIt->second;
 			if (const auto npcIt = npcFormIDMap.find(a_input.npcFormID); npcIt != npcFormIDMap.end()) {
 				auto& [levelCapState, levelMap] = npcIt->second;
@@ -156,7 +162,8 @@ namespace PCLevelMult
 
 	void Manager::DumpDistributedEntries()
 	{
-		for (auto& [playerID, npcFormIDs] : cache) {
+		Locker lock(_lock);
+	    for (auto& [playerID, npcFormIDs] : _cache) {
 			logger::info("PlayerID : {:X}", playerID);
 			for (auto& [npcFormID, levelMap] : npcFormIDs) {
 				logger::info("\tNPC : {} [{:X}]", Cache::EditorID::GetEditorID(npcFormID), npcFormID);
@@ -173,7 +180,8 @@ namespace PCLevelMult
 	// For spawned actors with FF reference IDs
 	void Manager::DeleteNPC(RE::FormID a_characterID)
 	{
-		auto& currentCache = cache[GetSingleton()->GetCurrentPlayerID()];
+		Locker lock(_lock);
+	    auto& currentCache = _cache[GetSingleton()->GetCurrentPlayerID()];
 		if (const auto it = currentCache.find(a_characterID); it != currentCache.end()) {
 			currentCache.erase(it);
 		}
@@ -183,7 +191,9 @@ namespace PCLevelMult
 	{
 		bool hitCap = (a_input.npcLevel == a_input.npcLevelCap);
 
-		auto& map = cache[a_input.playerID];
+		Locker lock(_lock);
+
+	    auto& map = _cache[a_input.playerID];
 		if (const auto it = map.find(a_input.npcFormID); it == map.end()) {
 			map[a_input.npcFormID].levelCapState = static_cast<LEVEL_CAP_STATE>(hitCap);
 		} else {
@@ -235,9 +245,10 @@ namespace PCLevelMult
 
 	void Manager::remap_player_ids(std::uint64_t a_oldID, std::uint64_t a_newID)
 	{
-		if (!cache.contains(a_newID)) {
-			if (const auto it = cache.find(a_oldID); it != cache.end()) {
-				cache[a_newID] = it->second;
+		Locker lock(_lock);
+	    if (!_cache.contains(a_newID)) {
+			if (const auto it = _cache.find(a_oldID); it != _cache.end()) {
+				_cache[a_newID] = it->second;
 			}
 		}
 	}
diff --git a/SPID/vcpkg.json b/SPID/vcpkg.json
index 7217b9d..c18c8e4 100644
--- a/SPID/vcpkg.json
+++ b/SPID/vcpkg.json
@@ -1,6 +1,6 @@
 {
   "name": "spid",
-  "version-string": "6.0.3",
+  "version-string": "6.1.0",
   "description": "Spell Perk Item Distributor",
   "homepage": "https://github.com/powerof3/Spell-Perk-Item-Distributor",
   "license": "MIT",