diff --git a/bar.c b/bar.c
index b68ca70..8012d35 100644
--- a/bar.c
+++ b/bar.c
@@ -324,8 +324,13 @@ run(struct bar *_bar)
     /* TODO: a lot of this (up to mapping the window) could be done in bar_new() */
     xcb_generic_error_t *e;
 
-    bar->conn = xcb_connect(NULL, NULL);
-    assert(bar->conn != NULL);
+    int default_screen;
+    bar->conn = xcb_connect(NULL, &default_screen);
+    if (xcb_connection_has_error(bar->conn) > 0) {
+        LOG_ERR("failed to connect to X");
+        xcb_disconnect(bar->conn);
+        return 1;
+    }
 
     const xcb_setup_t *setup = xcb_get_setup(bar->conn);
 
diff --git a/main.c b/main.c
index f80a30a..5fc1a55 100644
--- a/main.c
+++ b/main.c
@@ -119,6 +119,15 @@ main(int argc, const char *const *argv)
         return 1;
     }
 
+    /* Connect to XCB, to be able to detect a disconnect (allowing us
+     * to exit) */
+    xcb_connection_t *xcb = xcb_connect(NULL, NULL);
+    if (xcb_connection_has_error(xcb) > 0) {
+        LOG_ERR("failed to connect to X");
+        xcb_disconnect(xcb);
+        return 1;
+    }
+
     xcb_init();
 
     bar->abort_fd = abort_fd;
@@ -129,11 +138,6 @@ main(int argc, const char *const *argv)
     /* Now unblock. We should be only thread receiving SIGINT */
     pthread_sigmask(SIG_UNBLOCK, &signal_mask, NULL);
 
-    /* Connect to XCB, to be able to detect a disconnect (allowing us
-     * to exit) */
-    xcb_connection_t *xcb = xcb_connect(NULL, NULL);
-    assert(xcb != NULL);
-
     /* Wait for SIGINT, or XCB disconnect */
     while (!aborted) {
         struct pollfd fds[] = {
diff --git a/modules/i3.c b/modules/i3.c
index acf6a98..d02da17 100644
--- a/modules/i3.c
+++ b/modules/i3.c
@@ -376,7 +376,13 @@ run(struct module *mod)
 
     struct sockaddr_un addr = {.sun_family = AF_UNIX};
     {
-        xcb_connection_t *conn = xcb_connect(NULL, NULL);
+        int default_screen;
+        xcb_connection_t *conn = xcb_connect(NULL, &default_screen);
+        if (xcb_connection_has_error(conn) > 0) {
+            LOG_ERR("failed to connect to X");
+            xcb_disconnect(conn);
+            return 1;
+        }
 
         const xcb_setup_t *setup = xcb_get_setup(conn);
         xcb_screen_t *screen = xcb_setup_roots_iterator(setup).data;
diff --git a/modules/xwindow.c b/modules/xwindow.c
index 3114056..ec9a1a4 100644
--- a/modules/xwindow.c
+++ b/modules/xwindow.c
@@ -196,9 +196,11 @@ run(struct module *mod)
 {
     struct private *m = mod->private;
 
-    m->conn = xcb_connect(NULL, NULL);
-    if (m->conn == NULL) {
+    int default_screen;
+    m->conn = xcb_connect(NULL, &default_screen);
+    if (xcb_connection_has_error(m->conn) > 0) {
         LOG_ERR("failed to connect to X");
+        xcb_disconnect(m->conn);
         return 1;
     }
 
diff --git a/xcb.c b/xcb.c
index 3f2539f..a157c1a 100644
--- a/xcb.c
+++ b/xcb.c
@@ -48,8 +48,9 @@ bool
 xcb_init(void)
 {
     xcb_connection_t *conn = xcb_connect(NULL, NULL);
-    if (conn == NULL) {
+    if (xcb_connection_has_error(conn) > 0) {
         LOG_ERR("failed to connect to X");
+        xcb_disconnect(conn);
         return false;
     }