diff --git a/lean/components/config/project_config_manager.py b/lean/components/config/project_config_manager.py
index e66c2875..e68f26c4 100644
--- a/lean/components/config/project_config_manager.py
+++ b/lean/components/config/project_config_manager.py
@@ -77,8 +77,8 @@ def get_project_id_from_project_config(self, project_directory: Path) -> int:
                                       it indicates the directory is unavailable.
 
         Returns:
-            int: Returns the 'cloud-id' if available.
-                 If 'cloud-id' is missing, returns the negative of 'local-id'.
+            int: Returns the 'cloud-id' if available and the project it refers to still exists in the cloud.
+                 Otherwise returns the negative of 'local-id'.
                  If neither is found nor if project_directory is None, returns -1.
         """
         if project_directory is None:
@@ -87,14 +87,30 @@ def get_project_id_from_project_config(self, project_directory: Path) -> int:
         project_config = self.get_project_config(project_directory)
 
         cloud_id = project_config.get("cloud-id")
-        if cloud_id is not None:
+        if cloud_id is not None and self._cloud_project_exists(cloud_id):
             return cloud_id
 
-        local_id = project_config.get("local-id")
-        if local_id is not None:
-            return -local_id  # Local ID must be negative.
+        return -abs(int(project_config.get("local-id", 1)))
 
-        return -1  # Return -1 if no valid IDs are found
+    def _cloud_project_exists(self, cloud_id: int) -> bool:
+        """Returns whether a project still exists in the cloud.
+
+        A 'cloud-id' left behind by a project that no longer exists in the cloud identifies nothing,
+        and neither does one this user cannot reach, so it cannot be used as the id of the project that runs.
+
+        :param cloud_id: the cloud id to look up
+        :return: True if the cloud project exists, False if it does not or if it could not be looked up
+        """
+        from lean.container import container
+
+        try:
+            organization_id = container.organization_manager.try_get_working_organization_id()
+            container.api_client.projects.get(cloud_id, organization_id)
+            return True
+        except Exception as e:
+            container.logger.debug(f"ProjectConfigManager._cloud_project_exists(): cloud project {cloud_id} "
+                                   f"is unavailable, falling back to the local id: {e}")
+            return False
 
     def get_latest_live_directory(self, project_directory: Path) -> Path:
         """Returns the path of the latest live directory.
diff --git a/tests/components/config/test_lean_config_manager.py b/tests/components/config/test_lean_config_manager.py
index fdb4cfa0..e55aa473 100644
--- a/tests/components/config/test_lean_config_manager.py
+++ b/tests/components/config/test_lean_config_manager.py
@@ -27,6 +27,7 @@
 from lean.components.util.xml_manager import XMLManager
 from lean.container import container
 from lean.models.utils import DebuggingMethod
+from tests.conftest import initialize_container
 from tests.test_helpers import create_fake_lean_cli_directory
 
 
@@ -388,6 +389,21 @@ def test_get_complete_lean_config_returns_dict_with_all_keys_removed_in_clean_le
         assert key in config
 
 
+def test_get_complete_lean_config_sets_the_project_id_of_the_project_being_run() -> None:
+    create_fake_lean_cli_directory()
+    # the id of the project being run is only used when the Lean config does not set one
+    (Path.cwd() / "lean.json").write_text('{"data-folder": "data", "organization-id": "abc"}', encoding="utf-8")
+    initialize_container()
+
+    project_directory = Path.cwd() / "Python Project"
+    ProjectConfigManager(XMLManager()).get_project_config(project_directory).set("cloud-id", 1234)
+
+    manager = _create_lean_config_manager()
+    config = manager.get_complete_lean_config("backtesting", project_directory / "main.py", None)
+
+    assert config["project-id"] == 1234
+
+
 def test_get_complete_lean_config_sets_environment() -> None:
     create_fake_lean_cli_directory()
 
diff --git a/tests/components/config/test_project_config_manager.py b/tests/components/config/test_project_config_manager.py
index 48bd26ec..0c69d7d2 100644
--- a/tests/components/config/test_project_config_manager.py
+++ b/tests/components/config/test_project_config_manager.py
@@ -12,8 +12,11 @@
 # limitations under the License.
 
 from pathlib import Path
+from unittest import mock
 
 from lean.components.config.project_config_manager import ProjectConfigManager
+from lean.models.errors import RequestFailedError
+from tests.conftest import initialize_container
 from lean.components.util.xml_manager import XMLManager
 from lean.models.utils import CSharpLibrary
 from tests.test_helpers import create_fake_lean_cli_directory
@@ -118,3 +121,46 @@ def test_get_csharp_libraries_skips_invalid_package_reference_tags() -> None:
 
     assert len(libraries) == 1
     assert CSharpLibrary(name="QuantConnect.Lean", version="2.5.11586") in libraries
+
+
+def test_get_project_id_from_project_config_returns_negative_local_id() -> None:
+    create_fake_lean_cli_directory()
+
+    project_config_manager = ProjectConfigManager(XMLManager())
+    project_directory = Path.cwd() / "Python Project"
+    local_id = project_config_manager.get_local_id(project_directory)
+
+    assert project_config_manager.get_project_id_from_project_config(project_directory) == -local_id
+
+
+def test_get_project_id_from_project_config_returns_cloud_id_when_the_cloud_project_exists() -> None:
+    create_fake_lean_cli_directory()
+    initialize_container()
+
+    project_config_manager = ProjectConfigManager(XMLManager())
+    project_directory = Path.cwd() / "Python Project"
+    project_config_manager.get_project_config(project_directory).set("cloud-id", 1234)
+
+    assert project_config_manager.get_project_id_from_project_config(project_directory) == 1234
+
+
+def test_get_project_id_from_project_config_falls_back_to_local_id_when_the_cloud_project_is_gone() -> None:
+    """A cloud-id left behind by a project deleted in the cloud identifies nothing."""
+    create_fake_lean_cli_directory()
+    container = initialize_container()
+    container.api_client.projects.get.side_effect = RequestFailedError(mock.MagicMock())
+
+    project_config_manager = ProjectConfigManager(XMLManager())
+    project_directory = Path.cwd() / "Python Project"
+    project_config_manager.get_project_config(project_directory).set("cloud-id", 1234)
+    local_id = project_config_manager.get_local_id(project_directory)
+
+    assert project_config_manager.get_project_id_from_project_config(project_directory) == -local_id
+
+
+def test_get_project_id_from_project_config_returns_minus_one_without_a_project_directory() -> None:
+    create_fake_lean_cli_directory()
+
+    project_config_manager = ProjectConfigManager(XMLManager())
+
+    assert project_config_manager.get_project_id_from_project_config(None) == -1