diff --git a/bootstrap.bat b/bootstrap.bat
index 3d35eb8..4ef73c8 100644
--- a/bootstrap.bat
+++ b/bootstrap.bat
@@ -1 +1,33 @@
-@msbuild vs/builder.sln -m -p:Configuration=Release -noLogo -clp:ErrorsOnly;Verbosity=minimal
\ No newline at end of file
+@echo off
+Setlocal EnableDelayedExpansion
+
+set "vswhere_cmd=third-party\bin\vswhere.exe -nologo -prerelease -latest -property installationPath"
+
+for /F "tokens=* USEBACKQ" %%F in (`%vswhere_cmd%`) do (
+	set ret=%errorlevel%
+	if %errorlevel% neq 0 (
+		echo %%F
+		echo vswhere returned %ret%
+		exit /b 1
+	)
+
+	set installation_path=%%F
+
+	if "%installation_path%" == "" (
+		echo empty installation path
+		exit /b 1
+	)
+)
+
+set "opts="
+set "opts=%opts% vs/mob.sln"
+set "opts=%opts% -m "
+set "opts=%opts% -p:Configuration=Release"
+set "opts=%opts% -noLogo "
+set "opts=%opts% -p:UseMultiToolTask=true"
+set "opts=%opts% -p:EnforceProcessCountAcrossBuilds=true"
+set "opts=%opts% -clp:ErrorsOnly;Verbosity=minimal"
+
+set "vcvars=%installation_path%\VC\Auxiliary\Build\vcvarsall.bat"
+cmd /c ""%vcvars%" amd64 > NUL && msbuild %opts%"
+echo run `mob` to start building
diff --git a/src/conf.cpp b/src/conf.cpp
index 2dd4464..b49beef 100644
--- a/src/conf.cpp
+++ b/src/conf.cpp
@@ -277,13 +277,15 @@ void dump_available_options()
 
 bool try_parts(fs::path& check, const std::vector<std::string>& parts)
 {
-	for (std::size_t i=0; i<parts.size() - 1; ++i)
+	for (std::size_t i=0; i<parts.size(); ++i)
 	{
 		fs::path p = check;
 
 		for (std::size_t j=i; j<parts.size(); ++j)
 			p /= parts[j];
 
+		gcx().trace(context::conf, "trying parts " + p.string());
+
 		if (fs::exists(p))
 		{
 			check = p;
@@ -702,29 +704,38 @@ void check_missing_options()
 {
 	if (conf::mo_org().empty())
 	{
-		gcx().bail_out(context::conf,
-			"missing mo_org; either specify it the [options] section of "
-			"the ini or pass '-s options/mo_org=something'");
+		std::cerr
+			<< "missing mo_org; either specify it the [options] section of "
+			<< "the ini or pass '-s options/mo_org=something'\n";
+
+		throw bailed("");
 	}
 
 	if (conf::mo_branch().empty())
 	{
-		gcx().bail_out(context::conf,
-			"missing mo_branch; either specify it the [options] section of "
-			"the ini or pass '-s options/mo_org=something'");
+		std::cerr
+			<< "missing mo_branch; either specify it the [options] section of "
+			<< "the ini or pass '-s options/mo_org=something'\n";
+
+		throw bailed("");
 	}
 
 	if (paths::prefix().empty())
 	{
-		gcx().bail_out(context::conf,
-			"missing prefix; either specify it the [paths] section of "
-			"the ini or pass '-d path'");
+		std::cerr
+			<< "missing prefix; either specify it the [paths] section of "
+			<< "the ini or pass '-d path'\n";
+
+		throw bailed("");
 	}
 
 	for (auto&& [k, v] : g_versions)
 	{
 		if (v.empty())
-			gcx().bail_out(context::conf, "missing version for " + k);
+		{
+			std::cerr << "missing version for " << k << "\n";
+			throw bailed("");
+		}
 	}
 }
 
diff --git a/src/main.cpp b/src/main.cpp
index f208d1a..d0a9165 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -181,6 +181,16 @@ int run(int argc, char** argv)
 	{
 		if (auto r=handle_command_line(argc, argv))
 			return *r;
+	}
+	catch(bailed&)
+	{
+		// silent
+		return 1;
+	}
+
+
+	try
+	{
 
 		::SetConsoleCtrlHandler(signal_handler, TRUE);
 
@@ -208,8 +218,15 @@ int main(int argc, char** argv)
 {
 	int r = mob::run(argc, argv);
 
-	mob::gcx().debug(mob::context::generic,
-		"mob finished with exit code " + std::to_string(r));
+	if (r == 0)
+	{
+		mob::gcx().debug(mob::context::generic, "mob done");
+	}
+	else
+	{
+		mob::gcx().debug(mob::context::generic,
+			"mob finished with exit code " + std::to_string(r));
+	}
 
 	mob::dump_logs();
 
diff --git a/src/net.cpp b/src/net.cpp
index a5aa49a..7bb1726 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -72,7 +72,17 @@ void curl_downloader::start(const url& u, const fs::path& path)
 	if (conf::dry())
 		return;
 
-	thread_ = std::thread([&] { run(); });
+	thread_ = std::thread([&]
+	{
+		try
+		{
+			run();
+		}
+		catch(...)
+		{
+			// eat it
+		}
+	});
 }
 
 void curl_downloader::join()
@@ -104,6 +114,11 @@ void curl_downloader::run()
 	curl_easy_setopt(c, CURLOPT_URL, url_.c_str());
 	curl_easy_setopt(c, CURLOPT_WRITEFUNCTION, on_write_static);
 	curl_easy_setopt(c, CURLOPT_WRITEDATA, this);
+	curl_easy_setopt(c, CURLOPT_PROGRESSFUNCTION, on_progress_static);
+	curl_easy_setopt(c, CURLOPT_PROGRESSDATA, this);
+	curl_easy_setopt(c, CURLOPT_XFERINFOFUNCTION, on_xfer_static);
+	curl_easy_setopt(c, CURLOPT_XFERINFODATA, this);
+	curl_easy_setopt(c, CURLOPT_NOPROGRESS, 0l);
 	curl_easy_setopt(c, CURLOPT_FOLLOWLOCATION, 1l);
 	curl_easy_setopt(c, CURLOPT_ERRORBUFFER, error_buffer);
 
@@ -120,7 +135,11 @@ void curl_downloader::run()
 	const auto r = curl_easy_perform(c);
 	cx_.trace(context::net, "curl: transfer finished " + url_.string());
 
-	file_.reset();
+	if (file_)
+	{
+		::FlushFileBuffers(file_.get());
+		file_.reset();
+	}
 
 	if (interrupt_)
 	{
@@ -152,8 +171,8 @@ void curl_downloader::run()
 	{
 		cx_.error(context::net,
 			std::string("curl: ") +
-			curl_easy_strerror(r) + ", " + error_buffer + ", " +
-			url_.string());
+			curl_easy_strerror(r) + ", " + trim_copy(error_buffer) + " " +
+			"(" + url_.string() + ")");
 	}
 }
 
@@ -169,6 +188,13 @@ size_t curl_downloader::on_write_static(
 	}
 
 	self->on_write(ptr, size * nmemb);
+
+	if (self->interrupt_)
+	{
+		debug("downloader: interrupting");
+		return (size * nmemb) + 1; // force failure
+	}
+
 	return size * nmemb;
 }
 
@@ -179,11 +205,59 @@ void curl_downloader::on_write(char* ptr, std::size_t n) noexcept
 		op::create_directories(cx_, path_.parent_path());
 
 		cx_.trace(context::net, "opening " + path_.string());
-		file_.reset(_wfopen(path_.native().c_str(), L"wb"));
+
+		HANDLE h = ::CreateFileA(
+			path_.string().c_str(), GENERIC_WRITE, FILE_SHARE_READ,
+			nullptr, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, 0);
+
+		if (h == INVALID_HANDLE_VALUE)
+		{
+			const auto e = GetLastError();
+			cx_.error(context::net, "failed to open " + path_.string(), e);
+			interrupt_ = true;
+			return;
+		}
+
+		file_.reset(h);
 	}
 
 	bytes_ += n;
-	std::fwrite(ptr, n, 1, file_.get());
+
+	DWORD written = 0;
+	if (!::WriteFile(file_.get(), ptr, static_cast<DWORD>(n), &written, nullptr))
+	{
+		const auto e = GetLastError();
+		cx_.error(context::net, "failed to write to " + path_.string(), e);
+		interrupt_ = true;
+	}
+}
+
+int curl_downloader::on_progress_static(
+	void* user, double, double, double, double) noexcept
+{
+	auto* self = static_cast<curl_downloader*>(user);
+
+	if (self->interrupt_)
+	{
+		debug("downloader: interrupting");
+		return 1;
+	}
+
+	return 0;
+}
+
+int curl_downloader::on_xfer_static(
+	void* user, curl_off_t, curl_off_t, curl_off_t, curl_off_t) noexcept
+{
+	auto* self = static_cast<curl_downloader*>(user);
+
+	if (self->interrupt_)
+	{
+		debug("downloader: interrupting");
+		return 1;
+	}
+
+	return 0;
 }
 
 int curl_downloader::on_debug_static(
diff --git a/src/net.h b/src/net.h
index caa381b..c9d8ef5 100644
--- a/src/net.h
+++ b/src/net.h
@@ -48,7 +48,7 @@ private:
 	const context& cx_;
 	url url_;
 	fs::path path_;
-	file_ptr file_;
+	handle_ptr file_;
 	std::thread thread_;
 	std::size_t bytes_;
 	std::atomic<bool> interrupt_;
@@ -61,6 +61,13 @@ private:
 
 	void on_write(char* ptr, std::size_t n) noexcept;
 
+	static int on_progress_static(
+		void* user, double dltotal, double dlnow,
+		double ultotal, double ulnow) noexcept;
+
+	static int on_xfer_static(
+		void* user, curl_off_t dltotal, curl_off_t dlnow,
+		curl_off_t ultotal, curl_off_t ulnow) noexcept;
 
 	static int on_debug_static(
 		CURL* handle, curl_infotype type,
diff --git a/src/op.cpp b/src/op.cpp
index 680b810..3739684 100644
--- a/src/op.cpp
+++ b/src/op.cpp
@@ -484,13 +484,29 @@ void check(const context& cx, const fs::path& p)
 	if (p.empty())
 		cx.bail_out(context::fs, "path is empty");
 
-	if (p.native().starts_with(paths::prefix().native()))
+	auto is_inside = [](auto&& p, auto&& dir)
+	{
+		const std::string s = p.string();
+		const std::string prefix = dir.string();
+
+		if (s.size() < prefix.size())
+			return false;
+
+		const std::string scut = s.substr(0, prefix.size());
+
+		if (_stricmp(scut.c_str(), prefix.c_str()) != 0)
+			return false;
+
+		return true;
+	};
+
+	if (is_inside(p, paths::prefix()))
 		return;
 
-	if (p.native().starts_with(paths::temp_dir().native()))
+	if (is_inside(p, paths::temp_dir()))
 		return;
 
-	if (p.native().starts_with(paths::licenses().native()))
+	if (is_inside(p, paths::licenses()))
 		return;
 
 	cx.bail_out(context::fs, "path " + p.string() + " is outside prefix");
diff --git a/src/process.cpp b/src/process.cpp
index 454a46b..6e7d08e 100644
--- a/src/process.cpp
+++ b/src/process.cpp
@@ -607,7 +607,10 @@ void process::on_completed()
 
 	// success
 	if (code_ == 0)
+	{
+		cx_->trace(context::cmd, "process exit code is 0");
 		return;
+	}
 
 	if (flags_ & allow_failure)
 	{
diff --git a/src/tasks/sip.cpp b/src/tasks/sip.cpp
index 74394f4..f0f4515 100644
--- a/src/tasks/sip.cpp
+++ b/src/tasks/sip.cpp
@@ -46,12 +46,23 @@ void sip::do_clean_for_rebuild()
 }
 
 void sip::do_fetch()
+{
+	// downloading uses python.exe and so has to wait until it's built
+}
+
+void sip::do_build_and_install()
 {
 	download();
 
 	run_tool(extractor()
 		.file(download_file())
 		.output(source_path()));
+
+	generate();
+
+	op::copy_file_to_dir_if_better(cx(),
+		source_path() / "sip.h",
+		python::include_path());
 }
 
 void sip::download()
@@ -84,15 +95,6 @@ void sip::download()
 		.arg("sip==" + versions::sip())));
 }
 
-void sip::do_build_and_install()
-{
-	generate();
-
-	op::copy_file_to_dir_if_better(cx(),
-		source_path() / "sip.h",
-		python::include_path());
-}
-
 void sip::generate()
 {
 	const auto header = source_path() / "sip.h";
diff --git a/src/tasks/stylesheets.cpp b/src/tasks/stylesheets.cpp
index 3010367..60a4925 100644
--- a/src/tasks/stylesheets.cpp
+++ b/src/tasks/stylesheets.cpp
@@ -22,9 +22,11 @@ void stylesheets::do_fetch()
 
 	for (auto&& r : releases())
 	{
-		const auto file = run_tool(downloader(
-			"https://github.com/" + r.repo + "/" + r.name + "/releases/"
-			"download/v" + r.version + "/" + r.file + ".7z"));
+		const auto file = run_tool(downloader()
+			.url(
+				"https://github.com/" + r.repo + "/" + r.name + "/releases/"
+				"download/v" + r.version + "/" + r.file + ".7z")
+			.file(paths::cache() / (r.name + ".7z")));
 
 		run_tool(extractor()
 			.file(file)
diff --git a/src/tasks/task.cpp b/src/tasks/task.cpp
index 75b3490..15a65ad 100644
--- a/src/tasks/task.cpp
+++ b/src/tasks/task.cpp
@@ -232,7 +232,8 @@ void task::fetch()
 
 			if (!get_source_path().empty())
 			{
-				cx().info(context::generic, "patching");
+				cx().debug(context::generic, "patching");
+
 				run_tool(patcher()
 					.task(name())
 					.root(get_source_path()));
diff --git a/src/tools/downloader.cpp b/src/tools/downloader.cpp
index 574fe67..6075b0c 100644
--- a/src/tools/downloader.cpp
+++ b/src/tools/downloader.cpp
@@ -17,9 +17,13 @@ downloader::downloader(mob::url u)
 
 downloader& downloader::url(const mob::url& u)
 {
-	cx_->trace(context::net, "adding url " + u.string());
 	urls_.push_back(u);
+	return *this;
+}
 
+downloader& downloader::file(const fs::path& p)
+{
+	file_ = p;
 	return *this;
 }
 
@@ -34,28 +38,23 @@ void downloader::do_run()
 
 	cx_->trace(context::net, "looking for already downloaded files");
 
-	for (auto&& u : urls_)
+	if (!file_.empty())
 	{
-		const auto file = path_for_url(u);
-
-		if (fs::exists(file))
+		if (try_picking(file_))
+			return;
+	}
+	else
+	{
+		for (auto&& u : urls_)
 		{
-			if (conf::redownload())
+			const auto file = path_for_url(u);
+
+			if (try_picking(file))
 			{
-				cx_->trace(context::redownload, "deleting " + file.string());
-				op::delete_file(*cx_, file, op::optional);
-			}
-			else
-			{
-				cx_->trace(context::bypass, "picking " + file_.string());
 				file_ = file;
 				return;
 			}
 		}
-		else
-		{
-			cx_->trace(context::net, "no " + file.string());
-		}
 	}
 
 
@@ -67,19 +66,19 @@ void downloader::do_run()
 	// try them in order
 	for (auto&& u : urls_)
 	{
-		const fs::path file = path_for_url(u);
+		if (file_.empty())
+			file_ = path_for_url(u);
 
 		cx_->trace(context::net,
-			"trying " + u.string() + " into " + file.string());
+			"trying " + u.string() + " into " + file_.string());
 
-		dl_->start(u, file);
+		dl_->start(u, file_);
 		cx_->trace(context::net, "waiting for download");
 		dl_->join();
 
 		if (dl_->ok())
 		{
-			cx_->trace(context::net, "file " + file.string() + " downloaded");
-			file_ = file;
+			cx_->trace(context::net, "file " + file_.string() + " downloaded");
 			return;
 		}
 
@@ -102,6 +101,29 @@ void downloader::do_interrupt()
 		dl_->interrupt();
 }
 
+bool downloader::try_picking(const fs::path& file)
+{
+	if (fs::exists(file))
+	{
+		if (conf::redownload())
+		{
+			cx_->trace(context::redownload, "deleting " + file.string());
+			op::delete_file(*cx_, file, op::optional);
+		}
+		else
+		{
+			cx_->trace(context::bypass, "picking " + file_.string());
+			return true;
+		}
+	}
+	else
+	{
+		cx_->trace(context::net, "no " + file.string());
+	}
+
+	return false;
+}
+
 fs::path downloader::path_for_url(const mob::url& u) const
 {
 	std::string filename;
diff --git a/src/tools/tools.cpp b/src/tools/tools.cpp
index ddd9636..c8745c4 100644
--- a/src/tools/tools.cpp
+++ b/src/tools/tools.cpp
@@ -48,7 +48,7 @@ void tool::interrupt()
 {
 	if (!interrupted_)
 	{
-		cx_->info(context::interruption, "interrupting " + name_);
+		cx_->debug(context::interruption, "interrupting " + name_);
 		interrupted_ = true;
 		do_interrupt();
 	}
diff --git a/src/tools/tools.h b/src/tools/tools.h
index f51ba6a..fe90f81 100644
--- a/src/tools/tools.h
+++ b/src/tools/tools.h
@@ -49,6 +49,7 @@ public:
 	downloader(mob::url u);
 
 	downloader& url(const mob::url& u);
+	downloader& file(const fs::path& p);
 
 	fs::path result() const;
 
@@ -62,6 +63,7 @@ private:
 	std::vector<mob::url> urls_;
 
 	fs::path path_for_url(const mob::url& u) const;
+	bool try_picking(const fs::path& file);
 };
 
 
diff --git a/src/utility.cpp b/src/utility.cpp
index bf7188c..a446525 100644
--- a/src/utility.cpp
+++ b/src/utility.cpp
@@ -84,8 +84,15 @@ file_deleter::file_deleter(const context& cx, fs::path p)
 
 file_deleter::~file_deleter()
 {
-	if (delete_)
-		delete_now();
+	try
+	{
+		if (delete_)
+			delete_now();
+	}
+	catch(...)
+	{
+		// eat it
+	}
 }
 
 void file_deleter::delete_now()
@@ -109,8 +116,15 @@ directory_deleter::directory_deleter(const context& cx, fs::path p)
 
 directory_deleter::~directory_deleter()
 {
-	if (delete_)
-		delete_now();
+	try
+	{
+		if (delete_)
+			delete_now();
+	}
+	catch(...)
+	{
+		// eat it
+	}
 }
 
 void directory_deleter::delete_now()
diff --git a/vs/mob.vcxproj b/vs/mob.vcxproj
index e38dc6d..c90ed1b 100644
--- a/vs/mob.vcxproj
+++ b/vs/mob.vcxproj
@@ -73,7 +73,7 @@
       <SubSystem>Console</SubSystem>
       <EnableCOMDATFolding>true</EnableCOMDATFolding>
       <OptimizeReferences>true</OptimizeReferences>
-      <GenerateDebugInformation>false</GenerateDebugInformation>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
     </Link>
   </ItemDefinitionGroup>
   <ItemGroup>