diff --git a/src/window.c b/src/window.c
index 8e65ae0..1ca8490 100644
--- a/src/window.c
+++ b/src/window.c
@@ -1171,13 +1171,17 @@ WWindow *wManageWindow(WScreen *scr, WNativeWindow window)
 		/* to make sure the window receives it's new position after reparenting */
 		wWindowSynthConfigureNotify(wwin);
 	} else {
-		/* Wayland: record geometry from normal hints; frame stays NULL */
+		/* Wayland: record geometry from normal hints; frame stays NULL.
+		 * Phase 67: store workspace in wwin->workspace since there is no
+		 * frame->workspace slot; wWorkspaceForceChange uses this field
+		 * when frame is NULL to avoid NULL dereferences on WS switch. */
 		wwin->client.x      = x;
 		wwin->client.y      = y;
 		wwin->client.width  = width;
 		wwin->client.height = height;
 		wwin->frame_x = x;
 		wwin->frame_y = y;
+		wwin->workspace = workspace;
 	}
 
 	/* Setup descriptors and save window to internal lists */
diff --git a/src/window.h b/src/window.h
index 96a6bc4..42c74c0 100644
--- a/src/window.h
+++ b/src/window.h
@@ -294,6 +294,10 @@ typedef struct WWindow {
 	int icon_w, icon_h;
 	RImage *net_icon_image;			/* Window Image */
 	WNETWindowType window_type;		/* _NET_WM_WINDOW_TYPE (WNW_TYPE_*) */
+	/* Phase 67: workspace slot for Wayland path (frame is NULL, so
+	 * frame->workspace is unavailable; workspace operations use this
+	 * field instead when !frame). */
+	int workspace;
 } WWindow;
 
 #define HAS_TITLEBAR(w)		(!(WFLAGP((w), no_titlebar) || (w)->flags.fullscreen))
diff --git a/src/workspace.c b/src/workspace.c
index 39b3669..dfe333e 100644
--- a/src/workspace.c
+++ b/src/workspace.c
@@ -467,7 +467,10 @@ void wWorkspaceForceChange(WScreen * scr, int workspace)
 		 * but will create annoyance for every other application
 		 */
 		while (tmp) {
-			if (tmp->frame->workspace != workspace && !tmp->flags.selected) {
+			/* Phase 67: Wayland windows have no frame; use wwin->workspace
+			 * as the workspace slot when frame is NULL. */
+			int tmp_workspace = tmp->frame ? tmp->frame->workspace : tmp->workspace;
+			if (tmp_workspace != workspace && !tmp->flags.selected) {
 				/* unmap windows not on this workspace */
 				if ((tmp->flags.mapped || tmp->flags.shaded) &&
 				    !IS_OMNIPRESENT(tmp) && !tmp->flags.changing_workspace) {
@@ -480,7 +483,7 @@ void wWorkspaceForceChange(WScreen * scr, int workspace)
 				}
 				/* also unmap miniwindows not on this workspace */
 				if (!wPreferences.sticky_icons && tmp->flags.miniaturized &&
-				    tmp->icon && !IS_OMNIPRESENT(tmp)) {
+				    tmp->icon && !IS_OMNIPRESENT(tmp) && tmp->icon->core) {
 					wm_backend->window_unmap(tmp->icon->core->window);
 					tmp->icon->mapped = 0;
 				}
@@ -488,7 +491,10 @@ void wWorkspaceForceChange(WScreen * scr, int workspace)
 				if (IS_OMNIPRESENT(tmp)) {
 					WApplication *wapp = wApplicationOf(tmp->main_window);
 
-					tmp->frame->workspace = workspace;
+					if (tmp->frame)
+						tmp->frame->workspace = workspace;
+					else
+						tmp->workspace = workspace;
 
 					if (wapp) {
 						wapp->last_workspace = workspace;
diff --git a/tests/wl-smoke-test.sh b/tests/wl-smoke-test.sh
index ca81d56..a5b4783 100755
--- a/tests/wl-smoke-test.sh
+++ b/tests/wl-smoke-test.sh
@@ -55,6 +55,9 @@
 #  24. (Phase 66) XDG popup initial configure scheduled so context menus and
 #      autocomplete dropdowns can commit first buffer without stalling
 #      (build-only check — weston-simple-shm creates no popups).
+#  25. (Phase 67) WWindow.workspace added; wWorkspaceForceChange uses it as
+#      fallback when frame==NULL so workspace switching is safe in Wayland
+#      (build-only check — workspace switch requires keyboard shortcuts).
 #
 # This test grows as wl_backend vtable slots are implemented.
 #