diff --git a/studio/backend/main.py b/studio/backend/main.py
index 2b34b11fef..064e261753 100644
--- a/studio/backend/main.py
+++ b/studio/backend/main.py
@@ -193,6 +193,11 @@ if _STUDIO_ROOT_RESOLVED != _LEGACY_STUDIO_ROOT:
     if not os.environ.get("UNSLOTH_LLAMA_CPP_PATH"):
         os.environ["UNSLOTH_LLAMA_CPP_PATH"] = str(_STUDIO_ROOT_RESOLVED / "llama.cpp")
 
+# The studio bundles unsloth_zoo; declare unsloth present (as `import unsloth`
+# does) so its lazy submodule imports (export, hardware, mlx) and the
+# DiffusionGemma runner never trip the install guard on a clean install.
+os.environ.setdefault("UNSLOTH_IS_PRESENT", "1")
+
 import hashlib
 import mimetypes
 import re as _re
diff --git a/studio/backend/run.py b/studio/backend/run.py
index a883154c4a..a8e9a46a66 100644
--- a/studio/backend/run.py
+++ b/studio/backend/run.py
@@ -545,6 +545,11 @@ if _STUDIO_ROOT_RESOLVED != _LEGACY_STUDIO_ROOT:
     if not os.environ.get("UNSLOTH_LLAMA_CPP_PATH"):
         os.environ["UNSLOTH_LLAMA_CPP_PATH"] = str(_STUDIO_ROOT_RESOLVED / "llama.cpp")
 
+# The studio bundles unsloth_zoo; declare unsloth present (as `import unsloth`
+# does) so its lazy submodule imports (export, hardware, mlx) and the
+# DiffusionGemma runner never trip the install guard on a clean install.
+os.environ.setdefault("UNSLOTH_IS_PRESENT", "1")
+
 
 def _write_pid_file():
     """Write the current process PID to the studio PID file."""