diff --git a/inline_snapshot/_external.py b/inline_snapshot/_external.py
index 0051147b..2aa0775b 100644
--- a/inline_snapshot/_external.py
+++ b/inline_snapshot/_external.py
@@ -44,7 +44,10 @@ def list(self) -> Set[str]:
             return set()
 
     def persist(self, name):
-        file = self._lookup_path(name)
+        try:
+            file = self._lookup_path(name)
+        except HashError:
+            return
         if file.stem.endswith("-new"):
             stem = file.stem[:-4]
             file.rename(file.with_name(stem + file.suffix))
diff --git a/inline_snapshot/pytest_plugin.py b/inline_snapshot/pytest_plugin.py
index 396dcf85..1dfaafc9 100644
--- a/inline_snapshot/pytest_plugin.py
+++ b/inline_snapshot/pytest_plugin.py
@@ -35,6 +35,13 @@ def pytest_addoption(parser):
     )
 
 
+def xdist_running(config):
+    return (
+        hasattr(config.option, "numprocesses")
+        and config.option.numprocesses is not None
+    )
+
+
 def pytest_configure(config):
     flags = config.option.inline_snapshot.split(",")
     flags = [flag for flag in flags if flag]
@@ -44,7 +51,12 @@ def pytest_configure(config):
             f"--inline-snapshot-disable can not be combined with other flags ({','.join(flags)})"
         )
 
-    _inline_snapshot._active = not config.option.inline_snapshot_disable
+    if xdist_running(config) and flags:
+        raise pytest.UsageError(f"inline-snapshot can not be combined with xdist")
+
+    _inline_snapshot._active = not (
+        config.option.inline_snapshot_disable or xdist_running(config)
+    )
 
     _inline_snapshot._update_flags = _inline_snapshot.Flags(set(flags))
 
@@ -116,6 +128,14 @@ def pytest_assertrepr_compare(config, op, left, right):
 
 
 def pytest_terminal_summary(terminalreporter, exitstatus, config):
+
+    if xdist_running(config):
+        terminalreporter.section("inline snapshot")
+        terminalreporter.write(
+            "INFO: inline-snapshot was disabled because you used xdist\n"
+        )
+        return
+
     if not _inline_snapshot._active:
         return
 
@@ -157,6 +177,7 @@ def report(flag, message):
     )
 
     if _inline_snapshot._update_flags.change_something():
+
         count = {"create": 0, "fix": 0, "trim": 0, "update": 0}
 
         for snapshot in _inline_snapshot.snapshots.values():
diff --git a/tests/test_pytest_plugin.py b/tests/test_pytest_plugin.py
index 6066992d..db4882a4 100644
--- a/tests/test_pytest_plugin.py
+++ b/tests/test_pytest_plugin.py
@@ -360,3 +360,29 @@ def test_sub_snapshot():
 ================================================================== 1 passed, 1 error in <time> ==================================================================
 """
     )
+
+
+def test_persist_unknown_external(project):
+    project.setup(
+        """\
+from inline_snapshot import external, snapshot
+
+def test_sub_snapshot():
+    external("123*.png")
+    assert 1==snapshot(2)
+"""
+    )
+
+    result = project.run("--inline-snapshot=fix")
+
+    assert project.source == snapshot(
+        """\
+from inline_snapshot import external, snapshot
+
+def test_sub_snapshot():
+    external("123*.png")
+    assert 1==snapshot(1)
+"""
+    )
+
+    assert result.ret == 0
diff --git a/tests/test_xdist.py b/tests/test_xdist.py
new file mode 100644
index 00000000..01333728
--- /dev/null
+++ b/tests/test_xdist.py
@@ -0,0 +1,39 @@
+from inline_snapshot import snapshot
+
+
+def test_xdist(project):
+
+    project.setup(
+        """\
+
+def test_a():
+    assert 1==snapshot()
+"""
+    )
+
+    result = project.run("--inline-snapshot=create", "-n=auto")
+
+    assert "\n".join(result.stderr.lines).strip() == snapshot(
+        "ERROR: inline-snapshot can not be combined with xdist"
+    )
+
+    assert result.ret == 4
+
+
+def test_xdist_disabled(project):
+
+    project.setup(
+        """\
+
+def test_a():
+    assert 1==snapshot(1)
+"""
+    )
+
+    result = project.run("-n=auto")
+
+    assert result.report == snapshot(
+        "INFO: inline-snapshot was disabled because you used xdist"
+    )
+
+    assert result.ret == 0