diff --git a/movie_editor/backend/git_update.py b/movie_editor/backend/git_update.py
index f3ccfb7d..b922a3db 100644
--- a/movie_editor/backend/git_update.py
+++ b/movie_editor/backend/git_update.py
@@ -188,6 +188,12 @@ def install_requirements(timeout: int = 900) -> dict:
     req = REPO_ROOT / REQUIREMENTS
     if not req.is_file():
         return {"ran": False, "ok": True, "detail": "no requirements.txt in this checkout"}
+    # What is installed BEFORE, so the update can say what it changed. An update that
+    # silently moves a shared dependency is the worst kind: ComfyUI is full of compiled
+    # extensions (torch, comfy-kitchen, comfy-aimdo, onnxruntime, opencv) and a numpy or
+    # transformers bump under them does not raise — it segfaults, or corrupts memory, hours
+    # later, with nothing in the log connecting it to the update that caused it.
+    before = _pip_freeze()
     cmd = [sys.executable, "-m", "pip", "install", "--disable-pip-version-check",
            "-r", str(req)]
     try:
@@ -204,7 +210,49 @@ def install_requirements(timeout: int = 900) -> dict:
         return {"ran": True, "ok": False,
                 "detail": f"pip install failed — run it yourself:\n"
                           f"  {sys.executable} -m pip install -r {req}\n\n{tail}"}
-    return {"ran": True, "ok": True, "detail": (proc.stdout or "").strip()[-800:]}
+    changed = _pip_diff(before, _pip_freeze())
+    if changed:
+        print("[FunPack update] pip changed these packages: " + ", ".join(changed))
+    return {"ran": True, "ok": True, "changed": changed,
+            "detail": (("Changed: " + ", ".join(changed) + "\n\n") if changed else "")
+                      + (proc.stdout or "").strip()[-800:]}
+
+
+def _pip_freeze() -> dict:
+    """{name: version} for the environment ComfyUI is running in. {} if pip cannot be read —
+    an unreadable freeze must never block the install it was only meant to describe."""
+    try:
+        out = subprocess.run([sys.executable, "-m", "pip", "freeze",
+                              "--disable-pip-version-check"],
+                             capture_output=True, text=True, timeout=120)
+        if out.returncode != 0:
+            return {}
+        found = {}
+        for line in (out.stdout or "").splitlines():
+            if "==" in line:
+                name, _, ver = line.partition("==")
+                found[name.strip().lower()] = ver.strip()
+        return found
+    except Exception:  # noqa: BLE001
+        return {}
+
+
+def _pip_diff(before: dict, after: dict) -> list[str]:
+    """Human-readable list of what moved. Empty when nothing did, or when either side is
+    unknown — reporting every package as "new" because the freeze failed would be worse
+    than saying nothing."""
+    if not before or not after:
+        return []
+    out = []
+    for name, ver in sorted(after.items()):
+        was = before.get(name)
+        if was is None:
+            out.append(f"{name} {ver} (new)")
+        elif was != ver:
+            out.append(f"{name} {was} -> {ver}")
+    for name in sorted(set(before) - set(after)):
+        out.append(f"{name} {before[name]} (removed)")
+    return out
 
 
 def pull(branch: str | None = None, *, install_deps: bool = False) -> dict:
diff --git a/movie_editor/tests/test_git_update.py b/movie_editor/tests/test_git_update.py
index 290e21a5..29388c42 100644
--- a/movie_editor/tests/test_git_update.py
+++ b/movie_editor/tests/test_git_update.py
@@ -219,17 +219,65 @@ def test_install_uses_the_running_interpreter(monkeypatch, tmp_path):
     whatever else is on it — installing into the wrong environment succeeds and changes
     nothing."""
     from movie_editor.backend import git_update as gu
-    seen = {}
+    calls = []
 
     def fake_run(cmd, **kw):
-        seen["cmd"] = cmd
+        calls.append(cmd)
         return types.SimpleNamespace(returncode=0, stdout="ok", stderr="")
 
     monkeypatch.setattr(gu.subprocess, "run", fake_run)
     out = gu.install_requirements()
     assert out["ran"] and out["ok"]
-    assert seen["cmd"][0] == sys.executable
-    assert seen["cmd"][1:4] == ["-m", "pip", "install"]
+    # freeze / install / freeze — every one of them through THIS interpreter.
+    assert all(c[0] == sys.executable and c[1:3] == ["-m", "pip"] for c in calls)
+    install = [c for c in calls if c[3] == "install"]
+    assert len(install) == 1
+
+
+def test_the_install_reports_which_packages_moved(monkeypatch):
+    """An update that silently bumps a shared dependency is the worst kind: ComfyUI is full
+    of compiled extensions, and a numpy or transformers change under them does not raise —
+    it segfaults hours later with nothing connecting it to the update."""
+    from movie_editor.backend import git_update as gu
+    freezes = iter(["numpy==1.26.4\ntransformers==4.44.0\n",
+                    "numpy==2.1.0\ntransformers==5.0.1\ngguf==0.10.0\n"])
+
+    def fake_run(cmd, **kw):
+        if cmd[3] == "freeze":
+            return types.SimpleNamespace(returncode=0, stdout=next(freezes), stderr="")
+        return types.SimpleNamespace(returncode=0, stdout="ok", stderr="")
+
+    monkeypatch.setattr(gu.subprocess, "run", fake_run)
+    changed = gu.install_requirements()["changed"]
+    assert "numpy 1.26.4 -> 2.1.0" in changed
+    assert "transformers 4.44.0 -> 5.0.1" in changed
+    assert "gguf 0.10.0 (new)" in changed
+
+
+def test_an_unreadable_freeze_reports_nothing_rather_than_everything(monkeypatch):
+    """Reporting every package as new because pip freeze failed is worse than silence."""
+    from movie_editor.backend import git_update as gu
+
+    def fake_run(cmd, **kw):
+        if cmd[3] == "freeze":
+            return types.SimpleNamespace(returncode=1, stdout="", stderr="boom")
+        return types.SimpleNamespace(returncode=0, stdout="ok", stderr="")
+
+    monkeypatch.setattr(gu.subprocess, "run", fake_run)
+    out = gu.install_requirements()
+    assert out["ok"] and out["changed"] == []
+
+
+def test_nothing_changed_reports_nothing(monkeypatch):
+    from movie_editor.backend import git_update as gu
+    same = "numpy==2.1.0\ngguf==0.10.0\n"
+
+    def fake_run(cmd, **kw):
+        return types.SimpleNamespace(
+            returncode=0, stdout=(same if cmd[3] == "freeze" else "ok"), stderr="")
+
+    monkeypatch.setattr(gu.subprocess, "run", fake_run)
+    assert gu.install_requirements()["changed"] == []
 
 
 def test_a_failed_install_reports_the_command_and_never_raises(monkeypatch):
diff --git a/requirements.txt b/requirements.txt
index e6861fbf..c3377240 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,3 +1,9 @@
+# Version floors ONLY where FunPack needs one, and never a bare upgrade of anything the
+# rest of ComfyUI compiles against. `pip install -r` upgrades a package whose floor is not
+# met — on a rental full of native extensions (torch, comfy-kitchen, comfy-aimdo,
+# onnxruntime, opencv) a numpy or transformers bump under them does not raise, it segfaults
+# hours later. The updater now prints exactly which packages moved; check that line first
+# when a machine starts misbehaving after an update.
 transformers>=5.0.0
 huggingface_hub
 safetensors