diff --git a/extensions/replacer.cpp b/extensions/replacer.cpp
index 493f123..a110850 100644
--- a/extensions/replacer.cpp
+++ b/extensions/replacer.cpp
@@ -3,14 +3,18 @@
 #include "text.h"
 #include <cwctype>
 #include <fstream>
+#include <atomic>
+#include <filesystem>
+#include <process.h>
 
-std::shared_mutex m;
+std::atomic<std::filesystem::file_time_type> replaceFileLastWrite;
 
 struct
 {
 public:
 	void Put(std::wstring original, std::wstring replacement)
 	{
+		if (original.empty()) return;
 		Node* current = &root;
 		for (auto c : original)
 			if (Ignore(c));
@@ -43,32 +47,50 @@ private:
 	} root;
 } replacementTrie;
 
-void Parse(const std::wstring& file)
+int Parse(const std::wstring& file)
 {
-	std::lock_guard l(m);
+	replacementTrie = {};
+	int replacementCount = 0;
 	size_t end = 0;
 	while (true)
 	{
 		size_t original = file.find(L"|ORIG|", end);
 		size_t becomes = file.find(L"|BECOMES|", original);
-		end = file.find(L"|END|", becomes);
-		if (end != std::wstring::npos) replacementTrie.Put(file.substr(original + 6, becomes - original - 6), file.substr(becomes + 9, end - becomes - 9));
-		else break;
+		if ((end = file.find(L"|END|", becomes)) == std::wstring::npos) break;
+		replacementTrie.Put(file.substr(original + 6, becomes - original - 6), file.substr(becomes + 9, end - becomes - 9));
+		++replacementCount;
 	}
+	return replacementCount;
+}
+
+bool Replace(std::wstring& sentence)
+{
+	for (int i = 0; i < sentence.size(); ++i)
+		if (sentence.size() > 10000) return false; // defend against infinite looping
+		else if (auto[length, replacement] = replacementTrie.Lookup(sentence.substr(i)); !replacement.empty()) sentence.replace(i, length, replacement);
+	return true;
 }
 
 BOOL WINAPI DllMain(HMODULE hModule, DWORD ul_reason_for_call, LPVOID lpReserved)
 {
+	static HANDLE replacementFile; // not actually used to read/write, just to ensure it exists
 	switch (ul_reason_for_call)
 	{
 	case DLL_PROCESS_ATTACH:
 	{
-		std::vector<BYTE> file(std::istreambuf_iterator<char>(std::ifstream(REPLACE_SAVE_FILE, std::ios::binary)), {});
-		Parse(std::wstring((wchar_t*)file.data(), file.size() / sizeof(wchar_t)));
+		replacementFile = CreateFileA(REPLACE_SAVE_FILE, FILE_GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE, nullptr, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
+		std::vector<BYTE> file(std::istreambuf_iterator<char>(std::ifstream(REPLACE_SAVE_FILE, std::ios::in | std::ios::binary)), {});
+		if (Parse(std::wstring((wchar_t*)file.data(), file.size() / sizeof(wchar_t))) == 0)
+		{
+			std::ofstream(REPLACE_SAVE_FILE, std::ios::out | std::ios::binary | std::ios::trunc).write((char*)REPLACER_INSTRUCTIONS, wcslen(REPLACER_INSTRUCTIONS) * sizeof(wchar_t));
+			_spawnlp(_P_DETACH, "notepad", "notepad", REPLACE_SAVE_FILE, NULL); // show file to user
+		}
+		replaceFileLastWrite = std::filesystem::last_write_time(REPLACE_SAVE_FILE);
 	}
 	break;
 	case DLL_PROCESS_DETACH:
 	{
+		CloseHandle(replacementFile);
 	}
 	break;
 	}
@@ -77,24 +99,31 @@ BOOL WINAPI DllMain(HMODULE hModule, DWORD ul_reason_for_call, LPVOID lpReserved
 
 bool ProcessSentence(std::wstring& sentence, SentenceInfo)
 {
+	static std::shared_mutex m;
+
+	static_assert(std::has_unique_object_representations_v<decltype(replaceFileLastWrite)::value_type>);
+	if (!replaceFileLastWrite.compare_exchange_strong(std::filesystem::last_write_time(REPLACE_SAVE_FILE), std::filesystem::last_write_time(REPLACE_SAVE_FILE)))
+	{
+		std::lock_guard l(m);
+		std::vector<BYTE> file(std::istreambuf_iterator<char>(std::ifstream(REPLACE_SAVE_FILE, std::ios::in | std::ios::binary)), {});
+		Parse(std::wstring((wchar_t*)file.data(), file.size() / sizeof(wchar_t)));
+	}
+
 	std::shared_lock l(m);
-	for (int i = 0; i < sentence.size(); ++i)
-		if (sentence.size() > 10000) return false; // defend against infinite looping
-		else if (auto[length, replacement] = replacementTrie.Lookup(sentence.substr(i)); !replacement.empty()) sentence.replace(i, length, replacement);
-	return true;
+	return Replace(sentence);
 }
 
 TEST(
 	{
-		Parse(LR"(|ORIG|さよなら|BECOMES|goodbye|END|
+		assert(Parse(LR"(|ORIG| さよなら|BECOMES|goodbye|END|
 |ORIG|バカ|BECOMES|idiot|END|
-|ORIG|こんにちは|BECOMES|hello|END|)");
+|ORIG|こんにちは |BECOMES|hello|END|)") == 3);
 		std::wstring replaced = LR"(hello　
  さよなら バカ こんにちは)";
-		ProcessSentence(replaced, { nullptr });
-		assert(replaced.rfind(L"さよなら") == std::wstring::npos);
-		assert(replaced.rfind(L"バカ") == std::wstring::npos);
-		assert(replaced.rfind(L"こんにちは") == std::wstring::npos);
-		replacementTrie = {};
+		Replace(replaced);
+		assert(replaced.find(L"さよなら") == std::wstring::npos &&
+			replaced.find(L"バカ") == std::wstring::npos &&
+			replaced.find(L"こんにちは") == std::wstring::npos
+		);
 	}
 );
diff --git a/include/text.h b/include/text.h
index 73c27be..7d61bf9 100644
--- a/include/text.h
+++ b/include/text.h
@@ -84,6 +84,13 @@ inline auto ALWAYS_ON_TOP = u8"Keep this window on top";
 inline auto REGEX_FILTER = u8"Regex Filter";
 inline auto INVALID_REGEX = u8"Invalid regex";
 inline auto CURRENT_FILTER = u8"Currently filtering: ";
+inline auto REPLACER_INSTRUCTIONS = LR"(This file only does anything when the "Replacer" extension is used.
+Replacement commands must be formatted like this:
+|ORIG|original_text|BECOMES|replacement_text|END|
+All text in this file outside of a replacement command is ignored.
+Whitespace in original_text is ignored, but replacement_text can contain spaces, newlines, etc.
+This file must be encoded in Unicode (UTF-16 little endian).
+)";
 inline auto THREAD_LINKER = u8"Thread Linker";
 inline auto LINK = u8"Link";
 inline auto THREAD_LINK_FROM = u8"Thread number to link from";
diff --git a/release/SavedReplacements.txt b/release/SavedReplacements.txt
deleted file mode 100644
index f53e807..0000000
Binary files a/release/SavedReplacements.txt and /dev/null differ