diff --git a/src/tests/test_app_config.py b/src/tests/test_app_config.py
index 4a74cbc0d..24abdc5dc 100644
--- a/src/tests/test_app_config.py
+++ b/src/tests/test_app_config.py
@@ -125,9 +125,9 @@ def test_app_config_get_nonexistentstuff(config_app):
     with pytest.raises(YunohostValidationError):
         app_config_get(config_app, "main.components.nonexistent")
 
-    app_setting(config_app, "boolean", delete=True)
+    app_setting(config_app, "number", delete=True)
     with pytest.raises(YunohostError):
-        app_config_get(config_app, "main.components.boolean")
+        app_config_get(config_app, "main.components.number")
 
 
 def test_app_config_regular_setting(config_app):
diff --git a/src/utils/configpanel.py b/src/utils/configpanel.py
index 4e1e0e8ce..eb9455a80 100644
--- a/src/utils/configpanel.py
+++ b/src/utils/configpanel.py
@@ -601,6 +601,17 @@ class ConfigPanel:
         for _, section, option in config.iter_children():
             value = data = raw_settings.get(option.id, getattr(option, "default", None))
 
+            if isinstance(option, BaseInputOption) and option.id not in raw_settings:
+                if option.default is not None:
+                    value = option.default
+                elif option.type is OptionType.file or option.bind == "null":
+                    continue
+                else:
+                    raise YunohostError(
+                        f"Config panel question '{option.id}' should be initialized with a value during install or upgrade.",
+                        raw_msg=True,
+                    )
+
             if isinstance(data, dict):
                 # Settings data if gathered from bash "ynh_app_config_show"
                 # may be a custom getter that returns a dict with `value` or `current_value`