diff --git a/CHANGES b/CHANGES
index 0d06ff20..69e19d33 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,5 +1,6 @@
 23 January 2009
 
+* Better error messages when creating a session or window fails.
 * Oops. Return non-zero on error. Reported by Will Maier.
 
 21 January 2009
@@ -1001,7 +1002,7 @@
   (including mutt, emacs). No status bar yet and no key remapping or other
   customisation.
 
-$Id: CHANGES,v 1.231 2009-01-23 16:19:56 nicm Exp $
+$Id: CHANGES,v 1.232 2009-01-23 16:59:14 nicm Exp $
 
  LocalWords:  showw utf UTF fulvio ciriaco joshe OSC APC gettime abc DEF OA clr
  LocalWords:  rivo nurges lscm Erdely eol smysession mysession ek dstname RB ms
diff --git a/TODO b/TODO
index 2e5030ca..7fe47aca 100644
--- a/TODO
+++ b/TODO
@@ -86,5 +86,4 @@
 - document split-window -p and -l
 - UTF-8 combining characters don't work (probably should be width 1 but are
   listed as 2)
-- better error reporting from session_new etc
 - attach should have a flag to create session if it doesn't exist
diff --git a/cmd-attach-session.c b/cmd-attach-session.c
index 1a403c65..ad9ed857 100644
--- a/cmd-attach-session.c
+++ b/cmd-attach-session.c
@@ -1,4 +1,4 @@
-/* $Id: cmd-attach-session.c,v 1.23 2009-01-19 18:23:40 nicm Exp $ */
+/* $Id: cmd-attach-session.c,v 1.24 2009-01-23 16:59:14 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -62,7 +62,7 @@ cmd_attach_session_exec(struct cmd *self, struct cmd_ctx *ctx)
 	}
 
 	if (tty_open(&ctx->cmdclient->tty, &cause) != 0) {
-		ctx->error(ctx, "%s", cause);
+		ctx->error(ctx, "terminal open failed: %s", cause);
 		xfree(cause);
 		return (-1);
 	}
diff --git a/cmd-link-window.c b/cmd-link-window.c
index 9227221a..48ebf891 100644
--- a/cmd-link-window.c
+++ b/cmd-link-window.c
@@ -1,4 +1,4 @@
-/* $Id: cmd-link-window.c,v 1.27 2009-01-19 18:23:40 nicm Exp $ */
+/* $Id: cmd-link-window.c,v 1.28 2009-01-23 16:59:14 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -47,6 +47,7 @@ cmd_link_window_exec(struct cmd *self, struct cmd_ctx *ctx)
 	struct cmd_srcdst_data	*data = self->data;
 	struct session		*dst;
 	struct winlink		*wl_src, *wl_dst;
+	char			*cause;
 	int			 idx;
 
 	if ((wl_src = cmd_find_window(ctx, data->src, NULL)) == NULL)
@@ -89,9 +90,10 @@ cmd_link_window_exec(struct cmd *self, struct cmd_ctx *ctx)
 		}
 	}
 
-	wl_dst = session_attach(dst, wl_src->window, idx);
+	wl_dst = session_attach(dst, wl_src->window, idx, &cause);
 	if (wl_dst == NULL) {
-		ctx->error(ctx, "index in use: %d", idx);
+		ctx->error(ctx, "create session failed: %s", cause);
+		xfree(cause);
 		return (-1);
 	}
 
diff --git a/cmd-move-window.c b/cmd-move-window.c
index 65812b17..b7f02091 100644
--- a/cmd-move-window.c
+++ b/cmd-move-window.c
@@ -1,4 +1,4 @@
-/* $Id: cmd-move-window.c,v 1.4 2009-01-19 18:23:40 nicm Exp $ */
+/* $Id: cmd-move-window.c,v 1.5 2009-01-23 16:59:14 nicm Exp $ */
 
 /*
  * Copyright (c) 2008 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -50,6 +50,7 @@ cmd_move_window_exec(struct cmd *self, struct cmd_ctx *ctx)
 	struct client		*c;
 	u_int		 	 i;
 	int		 	 destroyed, idx;
+	char			*cause;
 
 	if ((wl_src = cmd_find_window(ctx, data->src, &src)) == NULL)
 		return (-1);
@@ -91,9 +92,10 @@ cmd_move_window_exec(struct cmd *self, struct cmd_ctx *ctx)
 		}
 	}
 
-	wl_dst = session_attach(dst, wl_src->window, idx);
+	wl_dst = session_attach(dst, wl_src->window, idx, &cause);
 	if (wl_dst == NULL) {
-		ctx->error(ctx, "index in use: %d", idx);
+		ctx->error(ctx, "attach window failed: %s", cause);
+		xfree(cause);
 		return (-1);
 	}
 
diff --git a/cmd-new-session.c b/cmd-new-session.c
index 322e8b4b..76dd5130 100644
--- a/cmd-new-session.c
+++ b/cmd-new-session.c
@@ -1,4 +1,4 @@
-/* $Id: cmd-new-session.c,v 1.37 2009-01-20 19:35:03 nicm Exp $ */
+/* $Id: cmd-new-session.c,v 1.38 2009-01-23 16:59:14 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -158,14 +158,18 @@ cmd_new_session_exec(struct cmd *self, struct cmd_ctx *ctx)
 	}
 
 	if (!data->flag_detached && tty_open(&c->tty, &cause) != 0) {
-		ctx->error(ctx, "%s", cause);
+		ctx->error(ctx, "open terminal failed: %s", cause);
 		xfree(cause);
 		return (-1);
 	}
 
 
-	if ((s = session_create(data->newname, cmd, cwd, sx, sy)) == NULL)
-	       	fatalx("session_create failed");
+	s = session_create(data->newname, cmd, cwd, sx, sy, &cause);
+	if (s == NULL) {
+		ctx->error(ctx, "create session failed: %s", cause);
+		xfree(cause);
+		return (-1);
+	}
 	if (data->winname != NULL) {
 		xfree(s->curw->window->name);
 		s->curw->window->name = xstrdup(data->winname);
diff --git a/cmd-new-window.c b/cmd-new-window.c
index 921a47d6..76872b5a 100644
--- a/cmd-new-window.c
+++ b/cmd-new-window.c
@@ -1,4 +1,4 @@
-/* $Id: cmd-new-window.c,v 1.30 2009-01-21 22:21:49 nicm Exp $ */
+/* $Id: cmd-new-window.c,v 1.31 2009-01-23 16:59:14 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -120,7 +120,7 @@ cmd_new_window_exec(struct cmd *self, struct cmd_ctx *ctx)
 	struct cmd_new_window_data	*data = self->data;
 	struct session			*s;
 	struct winlink			*wl;
-	char				*cmd, *cwd;
+	char				*cmd, *cwd, *cause;
 	int				 idx;
 
 	if (data == NULL)
@@ -168,9 +168,10 @@ cmd_new_window_exec(struct cmd *self, struct cmd_ctx *ctx)
 	else
 		cwd = ctx->cmdclient->cwd;
 
-	wl = session_new(s, data->name, cmd, cwd, idx);
+	wl = session_new(s, data->name, cmd, cwd, idx, &cause);
 	if (wl == NULL) {
-		ctx->error(ctx, "command failed: %s", cmd);
+		ctx->error(ctx, "create window failed: %s", cause);
+		xfree(cause);
 		return (-1);
 	}
 	if (!data->flag_detached) {
diff --git a/cmd-respawn-window.c b/cmd-respawn-window.c
index deccb6f8..8dcbfaea 100644
--- a/cmd-respawn-window.c
+++ b/cmd-respawn-window.c
@@ -1,4 +1,4 @@
-/* $Id: cmd-respawn-window.c,v 1.12 2009-01-19 18:23:40 nicm Exp $ */
+/* $Id: cmd-respawn-window.c,v 1.13 2009-01-23 16:59:14 nicm Exp $ */
 
 /*
  * Copyright (c) 2008 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -50,7 +50,7 @@ cmd_respawn_window_exec(struct cmd *self, struct cmd_ctx *ctx)
 	struct window_pane	*wp;
 	struct session		*s;
 	const char		*env[] = CHILD_ENVIRON;
-	char		 	 buf[256];
+	char		 	 buf[256], *cause;
 	u_int			 i;
 
 	if ((wl = cmd_find_window(ctx, data->target, &s)) == NULL)
@@ -77,8 +77,9 @@ cmd_respawn_window_exec(struct cmd *self, struct cmd_ctx *ctx)
  	window_destroy_panes(w);
 	TAILQ_INSERT_HEAD(&w->panes, wp, entry);
 	window_pane_resize(wp, w->sx, w->sy);
-	if (window_pane_spawn(wp, data->arg, NULL, env) != 0) {
-		ctx->error(ctx, "respawn failed: %s:%d", s->name, wl->idx);
+	if (window_pane_spawn(wp, data->arg, NULL, env, &cause) != 0) {
+		ctx->error(ctx, "respawn window failed: %s", cause);
+		xfree(cause);
 		return (-1);
 	}
 	screen_reinit(&wp->base);
diff --git a/cmd-split-window.c b/cmd-split-window.c
index bf725377..7471446c 100644
--- a/cmd-split-window.c
+++ b/cmd-split-window.c
@@ -1,4 +1,4 @@
-/* $Id: cmd-split-window.c,v 1.7 2009-01-21 19:38:51 nicm Exp $ */
+/* $Id: cmd-split-window.c,v 1.8 2009-01-23 16:59:14 nicm Exp $ */
 
 /*
  * Copyright (c) 2009 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -140,8 +140,7 @@ cmd_split_window_exec(struct cmd *self, struct cmd_ctx *ctx)
 	struct window			*w;
 	struct window_pane		*wp;
 	const char			*env[] = CHILD_ENVIRON;
-	char		 		 buf[256];
-	char				*cmd, *cwd;
+	char		 		 buf[256], *cmd, *cwd, *cause;
 	u_int				 i, hlimit, lines;
 
 	if ((wl = cmd_find_window(ctx, data->target, &s)) == NULL)
@@ -168,8 +167,10 @@ cmd_split_window_exec(struct cmd *self, struct cmd_ctx *ctx)
 		lines = (w->active->sy * data->percentage) / 100;
 
 	hlimit = options_get_number(&s->options, "history-limit");
-	if ((wp = window_add_pane(w, lines, cmd, cwd, env, hlimit)) == NULL) {
-		ctx->error(ctx, "command failed: %s", cmd);
+	wp = window_add_pane(w, lines, cmd, cwd, env, hlimit, &cause);
+	if (wp == NULL) {
+		ctx->error(ctx, "create pane failed: %s", cause);
+		xfree(cause);
 		return (-1);
 	}
 	server_redraw_window(w);
diff --git a/session.c b/session.c
index 9d381f38..d2984bc1 100644
--- a/session.c
+++ b/session.c
@@ -1,4 +1,4 @@
-/* $Id: session.c,v 1.51 2009-01-18 18:31:45 nicm Exp $ */
+/* $Id: session.c,v 1.52 2009-01-23 16:59:14 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -112,8 +112,8 @@ session_find(const char *name)
 
 /* Create a new session. */
 struct session *
-session_create(
-    const char *name, const char *cmd, const char *cwd, u_int sx, u_int sy)
+session_create(const char *name,
+    const char *cmd, const char *cwd, u_int sx, u_int sy, char **cause)
 {
 	struct session	*s;
 	u_int		 i;
@@ -145,7 +145,7 @@ session_create(
 		s->name = xstrdup(name);
 	else
 		xasprintf(&s->name, "%u", i);
-	if (session_new(s, NULL, cmd, cwd, -1) == NULL) {
+	if (session_new(s, NULL, cmd, cwd, -1, cause) == NULL) {
 		session_destroy(s);
 		return (NULL);
 	}
@@ -197,7 +197,7 @@ session_index(struct session *s, u_int *i)
 /* Create a new window on a session. */
 struct winlink *
 session_new(struct session *s,
-    const char *name, const char *cmd, const char *cwd, int idx)
+    const char *name, const char *cmd, const char *cwd, int idx, char **cause)
 {
 	struct window	*w;
 	const char	*env[] = CHILD_ENVIRON;
@@ -210,18 +210,22 @@ session_new(struct session *s,
 	env[0] = buf;
 
 	hlimit = options_get_number(&s->options, "history-limit");
-	w = window_create(name, cmd, cwd, env, s->sx, s->sy, hlimit);
+	w = window_create(name, cmd, cwd, env, s->sx, s->sy, hlimit, cause);
 	if (w == NULL)
 		return (NULL);
 
-	return (session_attach(s, w, idx));
+	return (session_attach(s, w, idx, cause));
 }
 
 /* Attach a window to a session. */
 struct winlink *
-session_attach(struct session *s, struct window *w, int idx)
+session_attach(struct session *s, struct window *w, int idx, char **cause)
 {
-	return (winlink_add(&s->windows, w, idx));
+	struct winlink	*wl;
+
+	if ((wl = winlink_add(&s->windows, w, idx)) == NULL)
+		xasprintf(cause, "index in use: %d", idx);
+	return (wl);
 }
 
 /* Detach a window from a session. */
diff --git a/tmux.h b/tmux.h
index 327552e9..a0590fdd 100644
--- a/tmux.h
+++ b/tmux.h
@@ -1,4 +1,4 @@
-/* $Id: tmux.h,v 1.247 2009-01-21 22:47:31 nicm Exp $ */
+/* $Id: tmux.h,v 1.248 2009-01-23 16:59:14 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -1419,12 +1419,12 @@ void		 winlink_stack_push(struct winlink_stack *, struct winlink *);
 void		 winlink_stack_remove(struct winlink_stack *, struct winlink *);
 int	 	 window_index(struct window *, u_int *);
 struct window	*window_create(const char *, const char *,
-		     const char *, const char **, u_int, u_int, u_int);
+		     const char *, const char **, u_int, u_int, u_int, char **);
 void		 window_destroy(struct window *);
 int		 window_resize(struct window *, u_int, u_int);
 void		 window_set_active_pane(struct window *, struct window_pane *);
 struct window_pane *window_add_pane(struct window *, int,
-    		     const char *, const char *, const char **, u_int);
+		     const char *, const char *, const char **, u_int, char **);
 void		 window_remove_pane(struct window *, struct window_pane *);
 u_int		 window_index_of_pane(struct window *, struct window_pane *);
 struct window_pane *window_pane_at_index(struct window *, u_int);
@@ -1435,7 +1435,7 @@ void		 window_destroy_panes(struct window *);
 struct window_pane *window_pane_create(struct window *, u_int, u_int, u_int);
 void		 window_pane_destroy(struct window_pane *);
 int		 window_pane_spawn(struct window_pane *,
-		     const char *, const char *, const char **);
+		     const char *, const char *, const char **, char **);
 int		 window_pane_resize(struct window_pane *, u_int, u_int);
 void		 window_calculate_sizes(struct window *);
 int		 window_pane_set_mode(
@@ -1478,13 +1478,14 @@ void	 session_alert_cancel(struct session *, struct winlink *);
 int	 session_alert_has(struct session *, struct winlink *, int);
 int	 session_alert_has_window(struct session *, struct window *, int);
 struct session	*session_find(const char *);
-struct session	*session_create(
-    		     const char *, const char *, const char *, u_int, u_int);
+struct session	*session_create(const char *, const char *,
+    		     const char *, u_int, u_int, char **);
 void	 	 session_destroy(struct session *);
 int	 	 session_index(struct session *, u_int *);
 struct winlink	*session_new(struct session *, 
-		     const char *, const char *, const char *, int);
-struct winlink	*session_attach(struct session *, struct window *, int);
+	    	     const char *, const char *, const char *, int, char **);
+struct winlink	*session_attach(
+    		     struct session *, struct window *, int, char **);
 int		 session_detach(struct session *, struct winlink *);
 int		 session_has(struct session *, struct window *);
 int		 session_next(struct session *, int);
diff --git a/window.c b/window.c
index f9c2870e..9eb96e25 100644
--- a/window.c
+++ b/window.c
@@ -1,4 +1,4 @@
-/* $Id: window.c,v 1.61 2009-01-21 19:38:51 nicm Exp $ */
+/* $Id: window.c,v 1.62 2009-01-23 16:59:14 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicm@users.sourceforge.net>
@@ -19,6 +19,7 @@
 #include <sys/types.h>
 #include <sys/ioctl.h>
 
+#include <errno.h>
 #include <fcntl.h>
 #include <signal.h>
 #include <stdint.h>
@@ -200,13 +201,14 @@ window_index(struct window *s, u_int *i)
 }
 
 struct window *
-window_create(const char *name, const char *cmd,
-    const char *cwd, const char **envp, u_int sx, u_int sy, u_int hlimit)
+window_create(const char *name, const char *cmd, const char *cwd,
+    const char **envp, u_int sx, u_int sy, u_int hlimit, char **cause)
 {
 	struct window	*w;
 	u_int		 i;
 
 	w = xmalloc(sizeof *w);
+	w->name = NULL;
 	w->flags = 0;
 
 	TAILQ_INIT(&w->panes);
@@ -228,7 +230,7 @@ window_create(const char *name, const char *cmd,
 		ARRAY_ADD(&windows, w);
 	w->references = 0;
 
-	if (window_add_pane(w, -1, cmd, cwd, envp, hlimit) == NULL) {
+	if (window_add_pane(w, -1, cmd, cwd, envp, hlimit, cause) == NULL) {
 		window_destroy(w);
 		return (NULL);
 	}
@@ -256,8 +258,9 @@ window_destroy(struct window *w)
 	options_free(&w->options);
 
 	window_destroy_panes(w);
-	
-	xfree(w->name);
+
+	if (w->name != NULL)
+		xfree(w->name);
 	xfree(w);
 }
 
@@ -378,8 +381,8 @@ window_set_active_pane(struct window *w, struct window_pane *wp)
 }
 
 struct window_pane *
-window_add_pane(struct window *w, int wanty,
-    const char *cmd, const char *cwd, const char **envp, u_int hlimit)
+window_add_pane(struct window *w, int wanty, const char *cmd,
+    const char *cwd, const char **envp, u_int hlimit, char **cause)
 {
 	struct window_pane	*wp;
 	u_int			 sizey;
@@ -408,7 +411,7 @@ window_add_pane(struct window *w, int wanty,
 	else
 		TAILQ_INSERT_AFTER(&w->panes, w->active, wp, entry);
 	window_update_panes(w);
-	if (window_pane_spawn(wp, cmd, cwd, envp) != 0) {
+	if (window_pane_spawn(wp, cmd, cwd, envp, cause) != 0) {
 		window_remove_pane(w, wp);
 		return (NULL);
 	}
@@ -535,7 +538,7 @@ window_pane_destroy(struct window_pane *wp)
 
 int
 window_pane_spawn(struct window_pane *wp,
-    const char *cmd, const char *cwd, const char **envp)
+    const char *cmd, const char *cwd, const char **envp, char **cause)
 {
 	struct winsize	 ws;
 	int		 mode;
@@ -564,11 +567,13 @@ window_pane_spawn(struct window_pane *wp,
 		fatal("gettimeofday");
 	tv.tv_sec = 0;
 	tv.tv_usec = NAME_INTERVAL * 1000L;
-	timeradd(&wp->window->name_timer, &tv, &wp->window->name_timer);	
+	timeradd(&wp->window->name_timer, &tv, &wp->window->name_timer);
 
  	switch (forkpty(&wp->fd, NULL, NULL, &ws)) {
 	case -1:
-		return (1);
+		wp->fd = -1;
+		xasprintf(cause, "%s: %s", cmd, strerror(errno));
+		return (-1);
 	case 0:
 		if (chdir(wp->cwd) != 0)
 			chdir("/");