diff --git a/NEWS.rst b/NEWS.rst
index 9b320eba62ddd458efa952d1515ca9c82ac78eb5_TkVXUy5yc3Q=..929c7163031d8519158e35b4280d84a6951708d8_TkVXUy5yc3Q= 100644
--- a/NEWS.rst
+++ b/NEWS.rst
@@ -7,6 +7,8 @@
 
 Allow setting db_user, db_password, log_handler and pythondevmode in a global settings file (${XDG_CONFIG_HOME-$HOME/.config}/odoo_scripts/config.toml). Configuration can be done by odoo_type too.
 
+Detect missing package when preparing to build the image.
+
 20.4.0
 ------
 
diff --git a/odoo_scripts/docker_build_copy.py b/odoo_scripts/docker_build_copy.py
index 9b320eba62ddd458efa952d1515ca9c82ac78eb5_b2Rvb19zY3JpcHRzL2RvY2tlcl9idWlsZF9jb3B5LnB5..929c7163031d8519158e35b4280d84a6951708d8_b2Rvb19zY3JpcHRzL2RvY2tlcl9idWlsZF9jb3B5LnB5 100644
--- a/odoo_scripts/docker_build_copy.py
+++ b/odoo_scripts/docker_build_copy.py
@@ -15,5 +15,5 @@
 
 _logger = logging.getLogger(__name__)
 
-__version__ = "2.3.0"
+__version__ = "2.3.1"
 __date__ = "2020-06-30"
@@ -19,5 +19,5 @@
 __date__ = "2020-06-30"
-__updated__ = "2023-06-06"
+__updated__ = "2023-06-15"
 
 PYTHON_PACKAGES_DIR = "python_packages"
 
@@ -94,6 +94,11 @@
     # Try to include the CVS information in target so that setuptools-scm and
     # setuptools-odoo work as expected
     for package, options in c.python_packages.items():
+        if not os.path.exists(package):
+            raise Exception(
+                "Missing %s referenced in configuration. Forgot to run "
+                "confnest/confman?" % package
+            )
         if options["compile"] in ("True", "true") and (
             ci_mode or build_package_locally
         ):
diff --git a/pyproject.toml b/pyproject.toml
index 9b320eba62ddd458efa952d1515ca9c82ac78eb5_cHlwcm9qZWN0LnRvbWw=..929c7163031d8519158e35b4280d84a6951708d8_cHlwcm9qZWN0LnRvbWw= 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -11,6 +11,7 @@
   "Programming Language :: Python :: 3",
   "License :: OSI Approved :: MIT License",
   "Environment :: Console",
+  "Intended Audience :: Developers",
 ]
 keywords = ["odoo"]
 dependencies = [