diff --git a/src/cmd/build.rs b/src/cmd/build.rs
index 5fe73236..dacf45cf 100644
--- a/src/cmd/build.rs
+++ b/src/cmd/build.rs
@@ -2,6 +2,7 @@ use crate::{get_book_dir, open};
 use clap::{arg, App, Arg, ArgMatches};
 use mdbook::errors::Result;
 use mdbook::MDBook;
+use std::path::Path;
 
 // Create clap subcommand arguments
 pub fn make_subcommand<'help>() -> App<'help> {
@@ -39,11 +40,12 @@ pub fn execute(args: &ArgMatches) -> Result<()> {
     if args.is_present("open") {
         // FIXME: What's the right behaviour if we don't use the HTML renderer?
         let path = book.build_dir_for("html").join("index.html");
-        if !path.exists() {
-            error!("No chapter available to open");
-            std::process::exit(1)
+        if !Path::new(&path).exists() {
+            error!("Need a more descriptive error here: {:?}", path);
+            std::process::exit(1);
         }
-        open(path);
+
+        open(book.build_dir_for("html").join("index.html"));
     }
 
     Ok(())