diff --git a/tmux.h b/tmux.h
index c667f013d..b961b67d0 100644
--- a/tmux.h
+++ b/tmux.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: tmux.h,v 1.1421 2026/08/03 20:18:20 nicm Exp $ */
+/* $OpenBSD: tmux.h,v 1.1422 2026/08/05 08:54:56 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -1731,6 +1731,7 @@ struct tty_term {
 #define TERM_RGBCOLOURS 0x10
 #define TERM_VT100LIKE 0x20
 #define TERM_SIXEL 0x40
+#define TERM_INVALIDMS 0x80
 	int		 flags;
 
 	LIST_ENTRY(tty_term) entry;
diff --git a/tty-term.c b/tty-term.c
index 164b9f977..850adf31c 100644
--- a/tty-term.c
+++ b/tty-term.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tty-term.c,v 1.106 2026/06/13 09:17:29 nicm Exp $ */
+/* $OpenBSD: tty-term.c,v 1.107 2026/08/05 08:54:56 nicm Exp $ */
 
 /*
  * Copyright (c) 2008 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -31,6 +31,7 @@
 #include "tmux.h"
 
 static char	*tty_term_strip(const char *);
+static void	 tty_term_validate(struct tty_term *);
 
 struct tty_terms tty_terms = LIST_HEAD_INITIALIZER(tty_terms);
 
@@ -519,6 +520,26 @@ tty_term_apply_overrides(struct tty_term *term)
 		acs = "a#j+k+l+m+n+o-p-q-r-s-t+u+v+w+x|y<z>~.";
 	for (; acs[0] != '\0' && acs[1] != '\0'; acs += 2)
 		term->acs[(u_char) acs[0]][0] = acs[1];
+
+	tty_term_validate(term);
+}
+
+static void
+tty_term_validate(struct tty_term *term)
+{
+	struct tty_code	*code = &term->codes[TTYC_MS];
+
+	if (code->type != TTYCODE_STRING)
+		return;
+	if (*tty_term_string_ss(term, TTYC_MS, "c", "?") != '\0') {
+		term->flags &= ~TERM_INVALIDMS;
+		return;
+	}
+
+	log_debug("removing invalid Ms capability");
+	term->flags |= TERM_INVALIDMS;
+	free(code->value.string);
+	code->type = TTYCODE_NONE;
 }
 
 struct tty_term *
diff --git a/window-client.c b/window-client.c
index b94c22119..f42aa5b7a 100644
--- a/window-client.c
+++ b/window-client.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: window-client.c,v 1.47 2026/07/14 17:17:18 nicm Exp $ */
+/* $OpenBSD: window-client.c,v 1.48 2026/08/05 08:54:56 nicm Exp $ */
 
 /*
  * Copyright (c) 2017 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -113,14 +113,16 @@ static const char *window_client_info_lines[] = {
 	"#{?#{I/c:kmous},,#[align=right]unavailable: [kmous] missing}",
 
 	"#[fg=themelightgrey]set-clipboard #[#{E:tree-mode-border-style},acs]x#[default] "
-	"#{?#{!=:#{set-clipboard},off},#{?#{I/f:clipboard},,"
+	"#{?#{!=:#{set-clipboard},off},#{?#{I/c:Ms},,"
 	"#[fg=themered]}#{set-clipboard},#[fg=themelightgrey]off} "
-	"#{?#{I/f:clipboard},,#[align=right]unavailable: [Ms] missing}",
+	"#{?#{I/c:Ms},,#[align=right]unavailable: [Ms] "
+	"#{?clipboard_invalid,invalid,missing}}",
 
 	"#[fg=themelightgrey]get-clipboard #[#{E:tree-mode-border-style},acs]x#[default] "
-	"#{?#{!=:#{get-clipboard},off},#{?#{I/f:clipboard},,"
+	"#{?#{!=:#{get-clipboard},off},#{?#{I/c:Ms},,"
 	"#[fg=themered]}#{get-clipboard},#[fg=themelightgrey]off} "
-	"#{?#{I/f:clipboard},,#[align=right]unavailable: [Ms] missing}",
+	"#{?#{I/c:Ms},,#[align=right]unavailable: [Ms] "
+	"#{?clipboard_invalid,invalid,missing}}",
 
 	"#[fg=themelightgrey]focus-events  #[#{E:tree-mode-border-style},acs]x#[default] "
 	"#{?focus-events,#{?#{I/f:focus},,#[fg=themered]}on,#[fg=themelightgrey]off} "
@@ -273,6 +275,10 @@ window_client_draw_info(__unused void *modedata, void *itemdata,
 	char				*expanded;
 
 	ft = format_create_defaults(NULL, c, NULL, NULL, NULL);
+	if (c->tty.term->flags & TERM_INVALIDMS)
+		format_add(ft, "clipboard_invalid", "1");
+	else
+		format_add(ft, "clipboard_invalid", "0");
 
 	screen_write_cursormove(ctx, cx, cy, 0);
 	for (i = 0; i < nitems(window_client_info_lines); i++) {