diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9f7ba17..8017c6e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@ Note: Breaking changes between versions are indicated by "💥".
 
 ## Unreleased
 
+- [Fix] "The Compose file is invalid" error on mounting dev-only folders.
 - [Fix] CMS settings in development.
 
 ## v13.2.0 (2022-04-24)
diff --git a/tutor/commands/compose.py b/tutor/commands/compose.py
index ea2c0a3..53c0791 100644
--- a/tutor/commands/compose.py
+++ b/tutor/commands/compose.py
@@ -19,6 +19,7 @@ class ComposeJobRunner(jobs.BaseComposeJobRunner):
         self.project_name = ""
         self.docker_compose_files: t.List[str] = []
         self.docker_compose_job_files: t.List[str] = []
+        self.docker_compose_tmp_path = ""
 
     def docker_compose(self, *command: str) -> int:
         """
diff --git a/tutor/commands/dev.py b/tutor/commands/dev.py
index a3778cb..184b99b 100644
--- a/tutor/commands/dev.py
+++ b/tutor/commands/dev.py
@@ -18,10 +18,11 @@ class DevJobRunner(compose.ComposeJobRunner):
         """
         super().__init__(root, config)
         self.project_name = get_typed(self.config, "DEV_PROJECT_NAME", str)
+        self.docker_compose_tmp_path = tutor_env.pathjoin(self.root, "dev", "docker-compose.tmp.yml")
         self.docker_compose_files += [
             tutor_env.pathjoin(self.root, "local", "docker-compose.yml"),
             tutor_env.pathjoin(self.root, "dev", "docker-compose.yml"),
-            tutor_env.pathjoin(self.root, "local", "docker-compose.tmp.yml"),
+            self.docker_compose_tmp_path,
             tutor_env.pathjoin(self.root, "local", "docker-compose.override.yml"),
             tutor_env.pathjoin(self.root, "dev", "docker-compose.override.yml"),
         ]
diff --git a/tutor/commands/local.py b/tutor/commands/local.py
index f731049..5adda36 100644
--- a/tutor/commands/local.py
+++ b/tutor/commands/local.py
@@ -20,10 +20,11 @@ class LocalJobRunner(compose.ComposeJobRunner):
         """
         super().__init__(root, config)
         self.project_name = get_typed(self.config, "LOCAL_PROJECT_NAME", str)
+        self.docker_compose_tmp_path = tutor_env.pathjoin(self.root, "dev", "docker-compose.tmp.yml")
         self.docker_compose_files += [
             tutor_env.pathjoin(self.root, "local", "docker-compose.yml"),
             tutor_env.pathjoin(self.root, "local", "docker-compose.prod.yml"),
-            tutor_env.pathjoin(self.root, "local", "docker-compose.tmp.yml"),
+            self.docker_compose_tmp_path,
             tutor_env.pathjoin(self.root, "local", "docker-compose.override.yml"),
         ]
         self.docker_compose_job_files += [