diff --git a/pm/environment.py b/pm/environment.py
index 83c7d42461..0a12a25ef6 100644
--- a/pm/environment.py
+++ b/pm/environment.py
@@ -60,6 +60,15 @@ UNDATED_INDEX_HINT = ("the package index did not report upload times, which lock
                       "dependencies needs for its 3-day release-age check. Use https://pypi.org/simple "
                       "or a mirror that serves upload times (pip.conf index-url / UV_INDEX_URL), then retry.")
 
+# uv's own English diagnostic. A localized Windows tail (os error 1224) rides
+# along, but the marker that means "packages may be installed, only the
+# optional compile step failed" is this line. #124268
+_BYTECODE_COMPILE_MARKER = "failed to bytecode-compile"
+# Streamed uv output keeps only the last 2000 characters. Resolver markers are
+# stitched back if a later verbose flood evicts them; the bytecode marker has
+# to ride the same path or repair/bootstrap never sees the retry signal.
+_STREAM_TAIL_MARKERS = _RESOLVER_MARKERS + (_BYTECODE_COMPILE_MARKER,)
+
 
 class ResolutionConflict(InstallError):
     """uv's resolver proved the union has no valid solution."""
@@ -69,6 +78,20 @@ class BuildFailure(InstallError):
     """A package's build backend ran and failed."""
 
 
+def _is_bytecode_compile_failure(result: subprocess.CompletedProcess) -> bool:
+    """True when uv failed in the optional bytecode-compile step, not the install.
+
+    ``--compile-bytecode`` exists so the first user-facing import does not pay
+    compile cost (#100461). It is not required for a usable environment. Windows
+    real-time AV can lock uv's temporary compile script (os error 1224) after
+    the packages are already on disk (#124268).
+    """
+    if not result.returncode:
+        return False
+    text = f"{result.stderr or ''}\n{result.stdout or ''}".lower()
+    return _BYTECODE_COMPILE_MARKER in text
+
+
 def classify_uv_failure(stage: str, returncode: int, output: str) -> InstallError:
     """Turn a failed `uv <stage>` into the right classified error.
 
@@ -185,7 +208,7 @@ def _run_streaming(command: list[str], *, cwd: Path, env: dict[str, str],
                 # evicts it. Scan across read boundaries, never retain the full log.
                 if not conflict:
                     lowered = (tail + text).lower()
-                    conflict = next((marker for marker in _RESOLVER_MARKERS if marker in lowered), "")
+                    conflict = next((marker for marker in _STREAM_TAIL_MARKERS if marker in lowered), "")
                 tail = (tail + text)[-2000:]
                 output.write(text)
                 output.flush()
@@ -328,7 +351,12 @@ class PythonEnvironment:
                     except BaseException:
                         tail.close(False)
                         raise
-                    tail.close(result.returncode == 0)
+                    if "--compile-bytecode" in args and _is_bytecode_compile_failure(result):
+                        # Caller retries without the flag. A failure banner here
+                        # would report a recovered install as failed.
+                        tail.discard()
+                    else:
+                        tail.close(result.returncode == 0)
                     return result
                 return subprocess.run(command, cwd=native(cwd), env=env, capture_output=True,
                                       text=True, encoding="utf-8", errors="replace", timeout=timeout, check=False)
@@ -398,6 +426,17 @@ class PythonEnvironment:
         for group in sorted(set(groups)):
             command += ["--group", group]
         result = self._run(command, cwd=source, timeout=timeout)
+        if _is_bytecode_compile_failure(result):
+            # Compile is an optimization. Retry once without the flag so a
+            # locked temp script cannot fail pm repair/bootstrap. Imports
+            # compile lazily on first use.
+            if self.output is not None:
+                self.output.write(
+                    "Bytecode compile failed; retrying the install without it. "
+                    "Modules will compile on first import.\n"
+                )
+            fallback = [arg for arg in command if arg != "--compile-bytecode"]
+            result = self._run(fallback, cwd=source, timeout=timeout)
         if result.returncode:
             raise classify_uv_failure("sync", result.returncode, result.stderr or result.stdout)
 
diff --git a/pm/progress.py b/pm/progress.py
index 72706826d4..0b448a0ca1 100644
--- a/pm/progress.py
+++ b/pm/progress.py
@@ -90,6 +90,19 @@ class LiveTail:
     def flush(self) -> None:
         return None
 
+    def discard(self) -> None:
+        """Clear the status line without a success or failure verdict.
+
+        Used when a bytecode-compile failure will be retried. Closing as a
+        failure here would report a recovered install as failed.
+        """
+        if self._partial:
+            self._line(self._partial)
+            self._partial = ""
+        if self.live:
+            self._draw("")
+            self._emit("\r")
+
     def close(self, ok: bool) -> None:
         if self._partial:
             self._line(self._partial)
diff --git a/tests/pm/test_sync_bytecode_compile_fallback.py b/tests/pm/test_sync_bytecode_compile_fallback.py
new file mode 100644
index 0000000000..3705db1c3a
--- /dev/null
+++ b/tests/pm/test_sync_bytecode_compile_fallback.py
@@ -0,0 +1,211 @@
+"""uv --compile-bytecode is an optimization. A compile-step failure must not
+fail the dependency sync (#124268).
+
+Windows real-time AV can lock uv's temporary compile script (os error 1224)
+after packages are already installed. The sync has to retry once without the
+flag so pm repair/bootstrap still produce a usable environment.
+"""
+
+from __future__ import annotations
+
+import subprocess
+from pathlib import Path
+
+import pytest
+
+from pm.environment import PythonEnvironment
+from pm.package import InstallError
+
+
+_BYTECODE_STDERR = (
+    "error: Failed to bytecode-compile Python file in: "
+    "C:\\hermes\\cache\\uv\\venv\\Lib\\site-packages\n"
+    "  Caused by: Failed to create temporary script file\n"
+    "  Caused by: failed to write to file "
+    "`C:\\hermes\\cache\\uv\\.tmpKKlVim\\pip_compileall.py`: "
+    "The requested operation cannot be performed on a file with a "
+    "user-mapped section open. (os error 1224)\n"
+)
+
+
+def _env(tmp_path: Path) -> PythonEnvironment:
+    return PythonEnvironment(
+        uv=tmp_path / "uv",
+        python=tmp_path / "python",
+        destination=tmp_path / "venv",
+        cache=tmp_path / "cache",
+        env={},
+    )
+
+
+def _completed(args: list[str], returncode: int, stderr: str = "") -> subprocess.CompletedProcess:
+    return subprocess.CompletedProcess(args, returncode, stdout="", stderr=stderr)
+
+
+def test_sync_retries_without_bytecode_compile_when_that_step_fails(tmp_path, monkeypatch):
+    """A bytecode-compile failure is not an install failure. The retry omits
+    the flag and a clean second sync leaves the environment usable."""
+    calls: list[list[str]] = []
+
+    def fake_run(self, args, *, cwd, timeout):
+        calls.append(list(args))
+        if "--compile-bytecode" in args:
+            return _completed(args, 1, _BYTECODE_STDERR)
+        return _completed(args, 0)
+
+    monkeypatch.setattr(PythonEnvironment, "_run", fake_run)
+    _env(tmp_path).sync(tmp_path)
+
+    assert len(calls) == 2
+    assert "--compile-bytecode" in calls[0]
+    assert "--compile-bytecode" not in calls[1]
+    assert calls[1][0] == "sync"
+    assert "--all-packages" in calls[1]
+    assert "--frozen" in calls[1]
+
+
+def test_sync_does_not_retry_an_unrelated_uv_failure(tmp_path, monkeypatch):
+    calls: list[list[str]] = []
+
+    def fake_run(self, args, *, cwd, timeout):
+        calls.append(list(args))
+        return _completed(args, 1, "error: No solution found for the requested dependencies")
+
+    monkeypatch.setattr(PythonEnvironment, "_run", fake_run)
+    with pytest.raises(InstallError):
+        _env(tmp_path).sync(tmp_path)
+    assert len(calls) == 1
+    assert "--compile-bytecode" in calls[0]
+
+
+def test_sync_keeps_bytecode_compile_on_the_happy_path(tmp_path, monkeypatch):
+    calls: list[list[str]] = []
+
+    def fake_run(self, args, *, cwd, timeout):
+        calls.append(list(args))
+        return _completed(args, 0)
+
+    monkeypatch.setattr(PythonEnvironment, "_run", fake_run)
+    _env(tmp_path).sync(tmp_path, extras=("web",), groups=("dev",))
+
+    assert len(calls) == 1
+    assert "--compile-bytecode" in calls[0]
+    assert "--extra" in calls[0] and "web" in calls[0]
+    assert "--group" in calls[0] and "dev" in calls[0]
+
+
+def test_sync_recognizes_bytecode_failure_reported_only_on_stdout(tmp_path, monkeypatch):
+    calls: list[list[str]] = []
+
+    def fake_run(self, args, *, cwd, timeout):
+        calls.append(list(args))
+        if "--compile-bytecode" in args:
+            return subprocess.CompletedProcess(
+                args, 1, stdout="error: Failed to bytecode-compile Python file in: venv\n", stderr=""
+            )
+        return _completed(args, 0)
+
+    monkeypatch.setattr(PythonEnvironment, "_run", fake_run)
+    _env(tmp_path).sync(tmp_path)
+    assert len(calls) == 2
+    assert "--compile-bytecode" not in calls[1]
+
+
+def test_sync_fallback_keeps_selection_flags_and_warns(tmp_path, monkeypatch):
+    import io
+
+    calls: list[list[str]] = []
+
+    def fake_run(self, args, *, cwd, timeout):
+        calls.append(list(args))
+        if "--compile-bytecode" in args:
+            return _completed(args, 1, _BYTECODE_STDERR)
+        return _completed(args, 0)
+
+    monkeypatch.setattr(PythonEnvironment, "_run", fake_run)
+    notes = io.StringIO()
+    PythonEnvironment(
+        uv=tmp_path / "uv",
+        python=tmp_path / "python",
+        destination=tmp_path / "venv",
+        cache=tmp_path / "cache",
+        env={},
+        output=notes,
+    ).sync(tmp_path, extras=("web",), no_default_groups=True)
+
+    assert "--extra" in calls[1] and "web" in calls[1]
+    assert "--no-default-groups" in calls[1]
+    assert "--compile-bytecode" not in calls[1]
+    assert "retrying the install without it" in notes.getvalue()
+
+
+def test_bytecode_compile_failure_does_not_banner_the_status_as_failed(tmp_path, monkeypatch):
+    """The non-verbose repair path wraps uv in LiveTail. Closing that tail as
+    a failure before the retry paints a recovered sync as failed."""
+    import io
+
+    notes = io.StringIO()
+
+    def fake_stream(command, *, cwd, env, timeout, output):
+        output.write("error: Failed to bytecode-compile Python file in: venv\n")
+        return subprocess.CompletedProcess(
+            command, 1, "", "error: Failed to bytecode-compile Python file in: venv\n"
+        )
+
+    monkeypatch.setattr("pm.environment._run_streaming", fake_stream)
+    monkeypatch.setattr("pm.environment.verbose_output", lambda: False)
+    PythonEnvironment(
+        uv=tmp_path / "uv",
+        python=tmp_path / "python",
+        destination=tmp_path / "venv",
+        cache=tmp_path / "cache",
+        env={},
+        output=notes,
+    )._run(["sync", "--frozen", "--compile-bytecode"], cwd=tmp_path, timeout=30)
+
+    assert "✗" not in notes.getvalue()
+    assert "failed" not in notes.getvalue().lower()
+
+
+def test_streaming_tail_keeps_bytecode_marker_after_later_output(tmp_path):
+    """Repair and bootstrap stream uv output. The diagnostic tail is 2000
+    characters, and resolver markers are stitched back if verbose output
+    evicts them. The bytecode marker has to survive the same way or the
+    retry never runs on the path that actually failed (#124268)."""
+    import sys
+
+    from pm.environment import _run_streaming
+
+    code = (
+        "import sys\n"
+        "sys.stdout.write('error: Failed to bytecode-compile Python file in: venv\\n')\n"
+        "sys.stdout.write('N' * 4000 + '\\n')\n"
+        "sys.stdout.flush()\n"
+        "raise SystemExit(1)\n"
+    )
+    notes = __import__("io").StringIO()
+    result = _run_streaming(
+        [sys.executable, "-c", code],
+        cwd=tmp_path,
+        env={},
+        timeout=30,
+        output=notes,
+    )
+    assert result.returncode == 1
+    assert "failed to bytecode-compile" in (result.stderr or "").lower()
+
+
+def test_sync_raises_when_the_fallback_sync_also_fails(tmp_path, monkeypatch):
+    calls: list[list[str]] = []
+
+    def fake_run(self, args, *, cwd, timeout):
+        calls.append(list(args))
+        if "--compile-bytecode" in args:
+            return _completed(args, 1, _BYTECODE_STDERR)
+        return _completed(args, 1, "error: failed to download distribution")
+
+    monkeypatch.setattr(PythonEnvironment, "_run", fake_run)
+    with pytest.raises(InstallError, match="failed to download"):
+        _env(tmp_path).sync(tmp_path)
+    assert len(calls) == 2
+    assert "--compile-bytecode" not in calls[1]