Auto-dismount volumes on system sleep and screen lock on macOS

src/Main/Forms/Forms.cpp

@@ -1832,7 +1832,7 @@ PreferencesDialogBase::PreferencesDialogBase( wxWindow* parent, wxWindowID id, c
 	DismountOnScreenSaverCheckBox = new wxCheckBox( sbSizer13->GetStaticBox(), wxID_ANY, _("IDC_PREF_UNMOUNT_SCREENSAVER"), wxDefaultPosition, wxDefaultSize, 0 );
 	sbSizer13->Add( DismountOnScreenSaverCheckBox, 0, wxALL, 5 );
 
-	DismountOnPowerSavingCheckBox = new wxCheckBox( sbSizer13->GetStaticBox(), wxID_ANY, _("LINUX_ENTERING_POVERSAWING"), wxDefaultPosition, wxDefaultSize, 0 );
+	DismountOnPowerSavingCheckBox = new wxCheckBox( sbSizer13->GetStaticBox(), wxID_ANY, _("LINUX_ENTERING_POWERSAVING"), wxDefaultPosition, wxDefaultSize, 0 );
 	sbSizer13->Add( DismountOnPowerSavingCheckBox, 0, wxALL, 5 );
 
 

src/Main/Forms/PreferencesDialog.cpp

@@ -295,12 +295,16 @@ namespace VeraCrypt
 		CloseExplorerWindowsOnDismountCheckBox->Show (false);
 #endif
 
-#ifndef wxHAS_POWER_EVENTS
+		// On macOS, wxHAS_POWER_EVENTS is undefined but sleep is handled by a
+		// native observer (see MacOSXSleepLock), so keep the checkbox visible.
+#if !defined(wxHAS_POWER_EVENTS) && !defined(TC_MACOSX)
 		DismountOnPowerSavingCheckBox->Show (false);
 #endif
 
 #ifdef TC_MACOSX
-		DismountOnScreenSaverCheckBox->Show (false);
+		// On macOS this checkbox drives dismount on screen lock (see
+		// MacOSXSleepLock), so relabel it accordingly.
+		DismountOnScreenSaverCheckBox->SetLabel (LangString["IDC_PREF_UNMOUNT_SESSION_LOCKED"]);
 		DismountOnLogOffCheckBox->SetLabel (LangString["LINUX_VC_QUITS"]);
 		OpenExplorerWindowAfterMountCheckBox->SetLabel (LangString["LINUX_OPEN_FINDER"]);
 

src/Main/Forms/TrueCrypt.fbp

@@ -11134,7 +11134,7 @@
                                                                             <property name="gripper">0</property>
                                                                             <property name="hidden">0</property>
                                                                             <property name="id">wxID_ANY</property>
-                                                                            <property name="label">LINUX_ENTERING_POVERSAWING</property>
+                                                                            <property name="label">LINUX_ENTERING_POWERSAVING</property>
                                                                             <property name="max_size"></property>
                                                                             <property name="maximize_button">0</property>
                                                                             <property name="maximum_size"></property>

src/Main/GraphicUserInterface.cpp

@@ -30,6 +30,7 @@
 #include "FatalErrorHandler.h"
 #ifdef TC_MACOSX
 #include "MacOSXSecureTextFieldHotkeys.h"
+#include "MacOSXSleepLock.h"
 #endif
 #include "Forms/DeviceSelectionDialog.h"
 #include "Forms/KeyfileGeneratorDialog.h"
@@ -184,6 +185,7 @@ namespace VeraCrypt
 	{
 #ifdef TC_MACOSX
 		UninstallMacOSXSecureTextFieldHotkeys();
+		UninstallMacOSXSleepLockHandler();
 #endif
 		try
 		{
@@ -1038,6 +1040,38 @@ namespace VeraCrypt
 		}
 	}
 
+#ifdef TC_MACOSX
+	// Called from MacOSXSleepLock.mm on the main thread when the system is about
+	// to sleep. wxWidgets does not deliver wxEVT_POWER_SUSPENDING on macOS
+	// (wxHAS_POWER_EVENTS is undefined there), so this observer fills that gap.
+	// AutoDismountVolumes is called with alwaysForce=false so that the
+	// ForceAutoDismount preference decides whether volumes with open files are
+	// detached, matching the Windows auto-dismount events (bForceAutoDismount).
+	void OnMacOSXSystemWillSleep ()
+	{
+		if (Gui && Gui->GetPreferences().BackgroundTaskEnabled && Gui->GetPreferences().DismountOnPowerSaving)
+		{
+			VolumeInfoList mountedVolumes = Core->GetMountedVolumes();
+			if (!mountedVolumes.empty())
+				Gui->AutoDismountVolumes (mountedVolumes, false);
+		}
+	}
+
+	// Called from MacOSXSleepLock.mm on the main thread when the user session
+	// has been verified as locked. macOS has no equivalent of the Windows
+	// screen-saver polling used by MainFrame::OnTimer, so screen-lock dismount
+	// is wired up here instead. Force semantics as above.
+	void OnMacOSXScreenLocked ()
+	{
+		if (Gui && Gui->GetPreferences().BackgroundTaskEnabled && Gui->GetPreferences().DismountOnScreenSaver)
+		{
+			VolumeInfoList mountedVolumes = Core->GetMountedVolumes();
+			if (!mountedVolumes.empty())
+				Gui->AutoDismountVolumes (mountedVolumes, false);
+		}
+	}
+#endif
+
 	bool GraphicUserInterface::OnInit ()
 	{
 		Gui = this;
@@ -1193,6 +1227,11 @@ namespace VeraCrypt
 #ifdef wxHAS_POWER_EVENTS
 			Gui->Connect (wxEVT_POWER_SUSPENDING, wxPowerEventHandler (GraphicUserInterface::OnPowerSuspending));
 #endif
+#ifdef TC_MACOSX
+			// macOS lacks wxHAS_POWER_EVENTS; use native observers for sleep and
+			// screen lock so volumes can be auto-dismounted on those events.
+			InstallMacOSXSleepLockHandler();
+#endif
 
 			mMainFrame = new MainFrame (nullptr);
 #if defined(TC_UNIX)

src/Main/MacOSXSleepLock.h

@@ -0,0 +1,28 @@
+/*
+ Copyright (c) 2013-2026 AM Crypto. All rights reserved.
+
+ Governed by the Apache License 2.0 the full text of which is
+ contained in the file License.txt included in VeraCrypt binary and source
+ code distribution packages.
+*/
+
+#ifndef TC_HEADER_Main_MacOSXSleepLock
+#define TC_HEADER_Main_MacOSXSleepLock
+
+#ifdef TC_MACOSX
+namespace VeraCrypt
+{
+	// Register/unregister observers for system sleep and screen lock.
+	// Implemented in MacOSXSleepLock.mm.
+	void InstallMacOSXSleepLockHandler ();
+	void UninstallMacOSXSleepLockHandler ();
+
+	// Invoked by the observers above when the corresponding event occurs.
+	// Implemented on the C++ side (GraphicUserInterface.cpp) so that all
+	// wxWidgets / Core logic stays out of the Objective-C++ file.
+	void OnMacOSXSystemWillSleep ();
+	void OnMacOSXScreenLocked ();
+}
+#endif
+
+#endif // TC_HEADER_Main_MacOSXSleepLock

src/Main/MacOSXSleepLock.mm

@@ -0,0 +1,133 @@
+/*
+ Copyright (c) 2013-2026 AM Crypto. All rights reserved.
+
+ Governed by the Apache License 2.0 the full text of which is
+ contained in the file License.txt included in VeraCrypt binary and source
+ code distribution packages.
+*/
+
+#include "System.h"
+#include "MacOSXSleepLock.h"
+
+#ifdef TC_MACOSX
+#import <Cocoa/Cocoa.h>
+#import <ApplicationServices/ApplicationServices.h>
+
+// Queries the window server for the actual lock state of the current session.
+// The com.apple.screenIsLocked distributed notification can be posted by any
+// local process, so it is treated only as a hint and the dismount is performed
+// only if the session really is locked.
+static bool SessionIsLocked ()
+{
+	bool locked = false;
+	CFDictionaryRef session = CGSessionCopyCurrentDictionary ();
+	if (session)
+	{
+		CFTypeRef value = CFDictionaryGetValue (session, CFSTR ("CGSSessionScreenIsLocked"));
+		locked = value && CFGetTypeID (value) == CFBooleanGetTypeID () && CFBooleanGetValue ((CFBooleanRef) value);
+		CFRelease (session);
+	}
+	return locked;
+}
+
+@interface VCSleepLockObserver : NSObject
+- (void) systemWillSleep: (NSNotification *) notification;
+- (void) screenLocked: (NSNotification *) notification;
+- (void) dismountIfSessionLocked;
+@end
+
+@implementation VCSleepLockObserver
+
+// The callbacks below are entered from AppKit notification dispatch; a C++
+// exception must not unwind through those Objective-C frames, so every call
+// into VeraCrypt code is guarded here. The dismount is best-effort: showing
+// UI is not reliable while the session is locking or the system is going to
+// sleep, so failures are ignored.
+
+- (void) systemWillSleep: (NSNotification *) notification
+{
+	(void) notification;
+	try
+	{
+		VeraCrypt::OnMacOSXSystemWillSleep ();
+	}
+	catch (...) { }
+}
+
+- (void) screenLocked: (NSNotification *) notification
+{
+	(void) notification;
+	// The window server can update the session dictionary slightly after the
+	// notification is delivered, so if the session does not report itself as
+	// locked yet, re-check once after a short delay instead of giving up.
+	if (SessionIsLocked ())
+	{
+		[self dismountIfSessionLocked];
+	}
+	else
+	{
+		[NSObject cancelPreviousPerformRequestsWithTarget: self selector: @selector (dismountIfSessionLocked) object: nil];
+		[self performSelector: @selector (dismountIfSessionLocked) withObject: nil afterDelay: 1.0];
+	}
+}
+
+- (void) dismountIfSessionLocked
+{
+	if (!SessionIsLocked ())
+		return;
+
+	try
+	{
+		VeraCrypt::OnMacOSXScreenLocked ();
+	}
+	catch (...) { }
+}
+
+@end
+
+namespace VeraCrypt
+{
+	// Non-ARC build (see the .mm compile rule in Build/Include/Makefile.inc),
+	// so the observer is retained by alloc/init and released in Uninstall.
+	static VCSleepLockObserver *SleepLockObserver = nil;
+
+	void InstallMacOSXSleepLockHandler ()
+	{
+		if (SleepLockObserver)
+			return;
+
+		SleepLockObserver = [[VCSleepLockObserver alloc] init];
+
+		// System sleep (lid close, idle sleep, Apple menu > Sleep). Delivered on
+		// the main thread by NSWorkspace's own notification center, which only
+		// the system feeds (it is per-process, unlike the distributed center).
+		[[[NSWorkspace sharedWorkspace] notificationCenter]
+			addObserver: SleepLockObserver
+			selector: @selector (systemWillSleep:)
+			name: NSWorkspaceWillSleepNotification
+			object: nil];
+
+		// Screen lock. macOS exposes no public notification for this; the
+		// com.apple.screenIsLocked distributed notification is the long-standing
+		// de-facto mechanism used to detect it. It is untrusted input: the
+		// handler verifies the actual session lock state before dismounting.
+		[[NSDistributedNotificationCenter defaultCenter]
+			addObserver: SleepLockObserver
+			selector: @selector (screenLocked:)
+			name: @"com.apple.screenIsLocked"
+			object: nil];
+	}
+
+	void UninstallMacOSXSleepLockHandler ()
+	{
+		if (!SleepLockObserver)
+			return;
+
+		[NSObject cancelPreviousPerformRequestsWithTarget: SleepLockObserver];
+		[[[NSWorkspace sharedWorkspace] notificationCenter] removeObserver: SleepLockObserver];
+		[[NSDistributedNotificationCenter defaultCenter] removeObserver: SleepLockObserver];
+		[SleepLockObserver release];
+		SleepLockObserver = nil;
+	}
+}
+#endif

src/Main/Main.make

@@ -28,6 +28,7 @@ OBJS += FatalErrorHandler.o
 OBJS += GraphicUserInterface.o
 ifeq "$(PLATFORM)" "MacOSX"
 OBJS += MacOSXSecureTextFieldHotkeys.o
+OBJS += MacOSXSleepLock.o
 endif
 OBJS += VolumeHistory.o
 OBJS += Forms/AboutDialog.o