diff --git a/reactos/subsys/system/explorer/globals.h b/reactos/subsys/system/explorer/globals.h
index 9ff4a36c2e3..ca1cd14f3ef 100644
--- a/reactos/subsys/system/explorer/globals.h
+++ b/reactos/subsys/system/explorer/globals.h
@@ -50,7 +50,7 @@ extern struct ExplorerGlobals
 #define	LOG(x) \
 { \
 	if (g_Globals._log) _ftprintf(g_Globals._log, TEXT("%s\n"), (LPCTSTR)(x)); \
-	OutputDebugString(x); \
+	OutputDebugString(FmtString(TEXT("%s\n"), (LPCTSTR)(x))); \
 }
 
 
diff --git a/reactos/subsys/system/explorer/shell/entries.cpp b/reactos/subsys/system/explorer/shell/entries.cpp
index 45d991b8338..42a578a1ab5 100644
--- a/reactos/subsys/system/explorer/shell/entries.cpp
+++ b/reactos/subsys/system/explorer/shell/entries.cpp
@@ -102,6 +102,8 @@ Entry::~Entry()
  // read directory tree and expand to the given location
 Entry* Entry::read_tree(const void* path, SORT_ORDER sortOrder)
 {
+	CONTEXT("Entry::read_tree()");
+
 	HCURSOR old_cursor = SetCursor(LoadCursor(0, IDC_WAIT));
 
 	Entry* entry = this;
@@ -126,6 +128,8 @@ Entry* Entry::read_tree(const void* path, SORT_ORDER sortOrder)
 
 void Entry::read_directory(SORT_ORDER sortOrder)
 {
+	CONTEXT("Entry::read_directory(SORT_ORDER)");
+
 	 // call into subclass
 	read_directory();
 
@@ -282,6 +286,8 @@ void Entry::sort_directory(SORT_ORDER sortOrder)
 
 void Entry::smart_scan()
 {
+	CONTEXT("Entry::smart_scan()");
+
 	if (!_scanned) {
 		free_subentries();
 		read_directory(SORT_NAME);	// we could use IShellFolder2::GetDefaultColumn to determine sort order
diff --git a/reactos/subsys/system/explorer/shell/filechild.cpp b/reactos/subsys/system/explorer/shell/filechild.cpp
index 354d98fb8ed..16a15de733c 100644
--- a/reactos/subsys/system/explorer/shell/filechild.cpp
+++ b/reactos/subsys/system/explorer/shell/filechild.cpp
@@ -439,6 +439,8 @@ void FileChildWindow::activate_entry(Pane* pane, HWND hwnd)
 
 void FileChildWindow::scan_entry(Entry* entry, HWND hwnd)
 {
+	CONTEXT("FileChildWindow::scan_entry()");
+
 	int idx = ListBox_GetCurSel(_left_hwnd);
 	HCURSOR old_cursor = SetCursor(LoadCursor(0, IDC_WAIT));
 
diff --git a/reactos/subsys/system/explorer/shell/shellbrowser.cpp b/reactos/subsys/system/explorer/shell/shellbrowser.cpp
index 8597ec84131..8df17dc1a94 100644
--- a/reactos/subsys/system/explorer/shell/shellbrowser.cpp
+++ b/reactos/subsys/system/explorer/shell/shellbrowser.cpp
@@ -72,6 +72,8 @@ ShellBrowserChild::~ShellBrowserChild()
 
 LRESULT ShellBrowserChild::Init(LPCREATESTRUCT pcs)
 {
+	CONTEXT("ShellBrowserChild::Init()");
+
 	if (super::Init(pcs))
 		return 1;
 
@@ -105,6 +107,8 @@ LRESULT ShellBrowserChild::Init(LPCREATESTRUCT pcs)
 
 void ShellBrowserChild::InitializeTree()
 {
+	CONTEXT("ShellBrowserChild::InitializeTree()");
+
 	TreeView_SetImageList(_left_hwnd, _himlSmall, TVSIL_NORMAL);
 	TreeView_SetScrollTime(_left_hwnd, 100);
 
@@ -150,6 +154,8 @@ void ShellBrowserChild::InitializeTree()
 
 bool ShellBrowserChild::InitDragDrop()
 {
+	CONTEXT("ShellBrowserChild::InitDragDrop()");
+
 	_pDropTarget = new TreeDropTarget(_left_hwnd);
 
 	if (!_pDropTarget)
@@ -180,6 +186,8 @@ bool ShellBrowserChild::InitDragDrop()
 
 void ShellBrowserChild::OnTreeItemRClick(int idCtrl, LPNMHDR pnmh)
 {
+	CONTEXT("ShellBrowserChild::OnTreeItemRClick()");
+
 	TVHITTESTINFO tvhti;
 
 	GetCursorPos(&tvhti.pt);
@@ -196,6 +204,8 @@ void ShellBrowserChild::OnTreeItemRClick(int idCtrl, LPNMHDR pnmh)
 
 void ShellBrowserChild::Tree_DoItemMenu(HWND hwndTreeView, HTREEITEM hItem, LPPOINT pptScreen)
 {
+	CONTEXT("ShellBrowserChild::Tree_DoItemMenu()");
+
 	LPARAM itemData = TreeView_GetItemData(hwndTreeView, hItem);
 
 	if (itemData) {
@@ -273,6 +283,8 @@ void ShellBrowserChild::Tree_DoItemMenu(HWND hwndTreeView, HTREEITEM hItem, LPPO
 
 void ShellBrowserChild::OnTreeGetDispInfo(int idCtrl, LPNMHDR pnmh)
 {
+	CONTEXT("ShellBrowserChild::OnTreeGetDispInfo()");
+
 	LPNMTVDISPINFO lpdi = (LPNMTVDISPINFO)pnmh;
 	ShellEntry* entry = (ShellEntry*)lpdi->item.lParam;
 
@@ -307,6 +319,8 @@ void ShellBrowserChild::OnTreeGetDispInfo(int idCtrl, LPNMHDR pnmh)
 
 void ShellBrowserChild::OnTreeItemExpanding(int idCtrl, LPNMTREEVIEW pnmtv)
 {
+	CONTEXT("ShellBrowserChild::OnTreeItemExpanding()");
+
 	if (pnmtv->action == TVE_COLLAPSE)
         TreeView_Expand(_left_hwnd, pnmtv->itemNew.hItem, TVE_COLLAPSE|TVE_COLLAPSERESET);
     else if (pnmtv->action == TVE_EXPAND) {
@@ -330,6 +344,8 @@ void ShellBrowserChild::OnTreeItemExpanding(int idCtrl, LPNMTREEVIEW pnmtv)
 
 int ShellBrowserChild::InsertSubitems(HTREEITEM hParentItem, Entry* entry, IShellFolder* pParentFolder)
 {
+	CONTEXT("ShellBrowserChild::InsertSubitems()");
+
 	WaitCursor wait;
 
 	int cnt = 0;
@@ -381,6 +397,8 @@ int ShellBrowserChild::InsertSubitems(HTREEITEM hParentItem, Entry* entry, IShel
 
 void ShellBrowserChild::OnTreeItemSelected(int idCtrl, LPNMTREEVIEW pnmtv)
 {
+	CONTEXT("ShellBrowserChild::OnTreeItemSelected()");
+
 	ShellEntry* entry = (ShellEntry*)pnmtv->itemNew.lParam;
 
 	_last_sel = pnmtv->itemNew.hItem;
@@ -402,6 +420,8 @@ void ShellBrowserChild::OnTreeItemSelected(int idCtrl, LPNMTREEVIEW pnmtv)
 
 void ShellBrowserChild::UpdateFolderView(IShellFolder* folder)
 {
+	CONTEXT("ShellBrowserChild::UpdateFolderView()");
+
 	FOLDERSETTINGS fs;
 	IShellView* pLastShellView = _pShellView;
 
@@ -467,6 +487,8 @@ int ShellBrowserChild::Notify(int id, NMHDR* pnmh)
 
 HRESULT ShellBrowserChild::OnDefaultCommand(LPIDA pIDList)
 {
+	CONTEXT("ShellBrowserChild::OnDefaultCommand()");
+
 	if (pIDList->cidl>=1) {
 		if (_left_hwnd) {	// explorer mode
 			if (_last_sel) {
@@ -506,6 +528,8 @@ HRESULT ShellBrowserChild::OnDefaultCommand(LPIDA pIDList)
 
 bool ShellBrowserChild::expand_folder(ShellDirectory* entry)
 {
+	CONTEXT("ShellBrowserChild::expand_folder()");
+
 	//HTREEITEM hitem_sel = TreeView_GetSelection(_left_hwnd);
 	if (!_last_sel)
 		return false;
diff --git a/reactos/subsys/system/explorer/shell/shellfs.cpp b/reactos/subsys/system/explorer/shell/shellfs.cpp
index 36b7dee7631..5b47dd9872c 100644
--- a/reactos/subsys/system/explorer/shell/shellfs.cpp
+++ b/reactos/subsys/system/explorer/shell/shellfs.cpp
@@ -37,6 +37,8 @@
 
 bool ShellDirectory::fill_w32fdata_shell(LPCITEMIDLIST pidl, SFGAOF attribs, WIN32_FIND_DATA* pw32fdata, BY_HANDLE_FILE_INFORMATION* pbhfi, bool do_access)
 {
+	CONTEXT("ShellDirectory::fill_w32fdata_shell()");
+
 	bool bhfi_valid = false;
 
 	if (do_access && !( (attribs&SFGAO_FILESYSTEM) && SUCCEEDED(
@@ -107,6 +109,8 @@ bool ShellDirectory::fill_w32fdata_shell(LPCITEMIDLIST pidl, SFGAOF attribs, WIN
 
 ShellPath ShellEntry::create_absolute_pidl() const
 {
+	CONTEXT("ShellEntry::create_absolute_pidl()");
+
 	if (_up/* && _up->_etype==ET_SHELL*/) {
 		ShellDirectory* dir = static_cast<ShellDirectory*>(_up);
 
@@ -130,6 +134,8 @@ void ShellEntry::get_path(PTSTR path) const
  // get full path of a shell folder
 void ShellDirectory::get_path(PTSTR path) const
 {
+	CONTEXT("ShellDirectory::get_path()");
+
 	path[0] = TEXT('\0');
 
 	SFGAOF attribs = 0;
@@ -174,6 +180,8 @@ BOOL ShellEntry::launch_entry(HWND hwnd, UINT nCmdShow)
 
 static HICON extract_icon(IShellFolder* folder, LPCITEMIDLIST pidl)
 {
+	CONTEXT("extract_icon()");
+
 	IExtractIcon* pExtract;
 
 	if (SUCCEEDED(folder->GetUIObjectOf(0, 1, (LPCITEMIDLIST*)&pidl, IID_IExtractIcon, 0, (LPVOID*)&pExtract))) {
@@ -229,6 +237,8 @@ static HICON extract_icon(IShellFolder* folder, LPCITEMIDLIST pidl)
 
 void ShellDirectory::read_directory()
 {
+	CONTEXT("ShellDirectory::read_directory()");
+
 	int level = _level + 1;
 
 	Entry* first_entry = NULL;
diff --git a/reactos/subsys/system/explorer/utility/shellclasses.cpp b/reactos/subsys/system/explorer/utility/shellclasses.cpp
index dd3964ba96b..80ab2db74ec 100644
--- a/reactos/subsys/system/explorer/utility/shellclasses.cpp
+++ b/reactos/subsys/system/explorer/utility/shellclasses.cpp
@@ -62,36 +62,47 @@ LPWSTR wcscpyn(LPWSTR dest, LPCWSTR source, size_t count)
 }
 
 
-Context Context::s_main(TEXT("-NO-CONTEXT-"));
+Context Context::s_main("-NO-CONTEXT-");
 Context* Context::s_current = &Context::s_main;
 
+String Context::toString() const
+{
+	FmtString str(TEXT("%hs"), _ctx);
+
+	if (!_obj.empty())
+		str.appendf(TEXT("\nObject: %s"), (LPCTSTR)_obj);
+
+	return str;
+}
+
+String Context::getStackTrace() const
+{
+	 // evtl. besser ostringstream verwenden
+	String str = TEXT("Context Trace:\n");
+
+	for(const Context*p=this; p!=&s_main; p=p->_last)
+		str.appendf(TEXT("ctx=%hs obj=%s\n"), p->_ctx, (LPCTSTR)p->_obj);
+
+	return str;
+}
 
- // Exception Handler for COM exceptions
 
 String COMException::toString() const
 {
 	TCHAR msg[4*BUFFER_LEN];
 	LPTSTR p = msg;
 
-	p += _stprintf(p, TEXT("%s"), super::ErrorMessage());
-
-	if (_ctx)
-		p += _stprintf(p, TEXT("\nContext: %s"), _ctx);
-
-	if (!_obj.empty())
-		p += _stprintf(p, TEXT("\nObject: %s"), (LPCTSTR)_obj);
+	p += _stprintf(p, TEXT("%s\nContext: %s"), super::ErrorMessage(), (LPCTSTR)_ctx.toString());
 
 	if (_file)
-#ifdef UNICODE
 		p += _stprintf(p, TEXT("\nLocation: %hs(%d)"), _file, _line);
-#else
-		p += _stprintf(p, TEXT("\nLocation: %s, line %d"), _file, _line);
-#endif
 
 	return msg;
 }
 
 
+ /// Exception Handler for COM exceptions
+
 void HandleException(COMException& e, HWND hwnd)
 {
 	String msg = e.toString();
diff --git a/reactos/subsys/system/explorer/utility/shellclasses.h b/reactos/subsys/system/explorer/utility/shellclasses.h
index bab3e8b874c..4137cedee97 100644
--- a/reactos/subsys/system/explorer/utility/shellclasses.h
+++ b/reactos/subsys/system/explorer/utility/shellclasses.h
@@ -102,45 +102,44 @@ struct COMException : public COMExceptionBase
 
 	COMException(HRESULT hr)
 	 :	super(hr),
-		_ctx(Context::current()._ctx),
-		_obj(Context::current()._obj),
+		_ctx(CURRENT_CONTEXT),
 		_file(NULL), _line(0)
 	{
 		LOG(toString());
+		LOG(CURRENT_CONTEXT.getStackTrace());
 	}
 
 	COMException(HRESULT hr, const char* file, int line)
 	 :	super(hr),
-		_ctx(Context::current()._ctx),
-		_obj(Context::current()._obj),
+		_ctx(CURRENT_CONTEXT),
 		_file(file), _line(line)
 	{
 		LOG(toString());
+		LOG(CURRENT_CONTEXT.getStackTrace());
 	}
 
 	COMException(HRESULT hr, const String& obj)
 	 :	super(hr),
-		_ctx(Context::current()._ctx),
-		_obj(obj),
+		_ctx(CURRENT_CONTEXT),
 		_file(NULL), _line(0)
 	{
-		_ctx = Context::current()._ctx;
+		_ctx = CURRENT_CONTEXT;
 		LOG(toString());
+		LOG(CURRENT_CONTEXT.getStackTrace());
 	}
 
 	COMException(HRESULT hr, const String& obj, const char* file, int line)
 	 :	super(hr),
-		_ctx(Context::current()._ctx),
-		_obj(obj),
+		_ctx(CURRENT_CONTEXT),
 		_file(file), _line(line)
 	{
 		LOG(toString());
+		LOG(CURRENT_CONTEXT.getStackTrace());
 	}
 
 	String toString() const;
 
-	LPCTSTR _ctx;
-	String	_obj;
+	Context _ctx;
 
 	const char* _file;
 	int _line;
diff --git a/reactos/subsys/system/explorer/utility/utility.cpp b/reactos/subsys/system/explorer/utility/utility.cpp
index 7ac569d7c53..f66a52d8d32 100644
--- a/reactos/subsys/system/explorer/utility/utility.cpp
+++ b/reactos/subsys/system/explorer/utility/utility.cpp
@@ -93,17 +93,17 @@ void MoveVisible(HWND hwnd)
 }
 
 
-void display_error(HWND hwnd, DWORD error)	//@@ CONTEXT mit ausgeben
+void display_error(HWND hwnd, DWORD error)	//@@ CONTEXT mit ausgeben -> display_error(HWND hwnd, const Exception& e)
 {
 	PTSTR msg;
 
 	if (FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER|FORMAT_MESSAGE_FROM_SYSTEM,
 		0, error, MAKELANGID(LANG_NEUTRAL,SUBLANG_DEFAULT), (PTSTR)&msg, 0, NULL)) {
-		LOG(msg);
+		LOG(FmtString(TEXT("display_error(%#x): %s"), error, msg));
 		MessageBox(hwnd, msg, TEXT("ROS Explorer"), MB_OK);
 	} else {
-		LOG(TEXT("display_error: Unknown Error"));
-		MessageBox(hwnd, TEXT("Unknown Error"), TEXT("ROS Explorer"), MB_OK);
+		LOG(FmtString(TEXT("Unknown Error %#x"), error));
+		MessageBox(hwnd, FmtString(TEXT("Unknown Error %#x"), error), TEXT("ROS Explorer"), MB_OK);
 	}
 
 	LocalFree(msg);
diff --git a/reactos/subsys/system/explorer/utility/utility.h b/reactos/subsys/system/explorer/utility/utility.h
index a1d5d55a2f4..b4a1f0e8200 100644
--- a/reactos/subsys/system/explorer/utility/utility.h
+++ b/reactos/subsys/system/explorer/utility/utility.h
@@ -85,7 +85,7 @@ using namespace _com_util;
 #define	BUFFER_LEN				1024
 
 
-#define	LOG(x) OutputDebugString(x)
+#define	LOG(x) 	OutputDebugString(FmtString(TEXT("%s\n"), (LPCTSTR)(x)));
 
 
  /// initialization of windows common controls
@@ -510,6 +510,60 @@ struct String
 	String& operator=(const super& s) {super::assign(s); return *this;}
 
 	operator LPCTSTR() const {return c_str();}
+
+	String& printf(LPCTSTR fmt, ...)
+	{
+		va_list l;
+		TCHAR b[BUFFER_LEN];
+
+		va_start(l, fmt);
+		super::assign(b, _vstprintf(b, fmt, l));
+		va_end(l);
+
+		return *this;
+	}
+
+	String& vprintf(LPCTSTR fmt, va_list l)
+	{
+		TCHAR b[BUFFER_LEN];
+
+		super::assign(b, _vstprintf(b, fmt, l));
+
+		return *this;
+	}
+
+	String& appendf(LPCTSTR fmt, ...)
+	{
+		va_list l;
+		TCHAR b[BUFFER_LEN];
+
+		va_start(l, fmt);
+		super::append(b, _vstprintf(b, fmt, l));
+		va_end(l);
+
+		return *this;
+	}
+
+	String& vappendf(LPCTSTR fmt, va_list l)
+	{
+		TCHAR b[BUFFER_LEN];
+
+		super::append(b, _vstprintf(b, fmt, l));
+
+		return *this;
+	}
+};
+
+struct FmtString : public String
+{
+	FmtString(LPCTSTR fmt, ...)
+	{
+		va_list l;
+
+		va_start(l, fmt);
+		vprintf(fmt, l);
+		va_end(l);
+	}
 };
 
 
@@ -571,14 +625,14 @@ protected:
 
 struct Context
 {
-	Context(LPCTSTR ctx)
+	Context(const char* ctx)
 	 :	_ctx(ctx)
 	{
 		_last = s_current;
 		s_current = this;
 	}
 
-	Context(LPCTSTR ctx, LPCSTR obj)
+	Context(const char* ctx, LPCSTR obj)
 	 :	_ctx(ctx),
 		_obj(obj)
 	{
@@ -586,7 +640,7 @@ struct Context
 		s_current = this;
 	}
 
-	Context(LPCTSTR ctx, LPCWSTR obj)
+	Context(const char* ctx, LPCWSTR obj)
 	 :	_ctx(ctx),
 		_obj(obj)
 	{
@@ -599,7 +653,10 @@ struct Context
 		s_current = _last;
 	}
 
-	LPCTSTR	_ctx;
+	String toString() const;
+	String getStackTrace() const;
+
+	const char* _ctx;
 	String	_obj;
 
 	static Context current() {return *s_current;}
@@ -612,8 +669,9 @@ protected:
 };
 
 #define	CONTEXT_OBJ __ctx__._obj
-#define	CONTEXT(c) Context __ctx__(TEXT(c))
-#define	OBJ_CONTEXT(c, o) Context __ctx__(TEXT(c), o);
+#define	CONTEXT(c) Context __ctx__(c)
+#define	CURRENT_CONTEXT Context::current()
+#define	OBJ_CONTEXT(c, o) Context __ctx__(c, o);
 
 
 #endif // __cplusplus