diff --git a/src/olympia/addons/management/commands/process_addons.py b/src/olympia/addons/management/commands/process_addons.py
index 3c8c84ebc8..a9159763ec 100644
--- a/src/olympia/addons/management/commands/process_addons.py
+++ b/src/olympia/addons/management/commands/process_addons.py
@@ -8,6 +8,7 @@ from olympia.addons.models import Addon
 from olympia.addons.tasks import (
     add_dynamic_theme_tag, add_firefox57_tag, bump_appver_for_legacy_addons,
     delete_addon_not_compatible_with_firefoxes,
+    disable_legacy_files,
     delete_obsolete_applicationsversions,
     find_inconsistencies_between_es_and_db,
     migrate_legacy_dictionaries_to_webextension,
@@ -90,6 +91,14 @@ tasks = {
               _current_version__files__is_webextension=False),
         ],
     },
+    'disable_legacy_files': {
+        'method': disable_legacy_files,
+        'qs': [
+            Q(type__in=(amo.ADDON_EXTENSION, amo.ADDON_THEME, amo.ADDON_LPAPP),
+              versions__files__is_webextension=False,
+              versions__files__is_mozilla_signed_extension=False)
+        ]
+    },
 }
 
 
diff --git a/src/olympia/addons/tasks.py b/src/olympia/addons/tasks.py
index 549006e438..c4ca289bfe 100644
--- a/src/olympia/addons/tasks.py
+++ b/src/olympia/addons/tasks.py
@@ -31,7 +31,7 @@ from olympia.applications.models import AppVersion
 from olympia.constants.categories import CATEGORIES
 from olympia.constants.licenses import (
     LICENSE_COPYRIGHT_AR, PERSONA_LICENSES_IDS)
-from olympia.files.models import FileUpload
+from olympia.files.models import File, FileUpload
 from olympia.files.utils import RDFExtractor, get_file, parse_addon, SafeZip
 from olympia.amo.celery import pause_all_tasks, resume_all_tasks
 from olympia.lib.crypto.packaged import sign_file
@@ -747,3 +747,23 @@ def migrate_legacy_dictionary_to_webextension(addon):
     file_ = version.all_files[0]
     sign_file(file_)
     file_.update(datestatuschanged=now, reviewed=now, status=amo.STATUS_PUBLIC)
+
+
+@task
+@use_primary_db
+def disable_legacy_files(ids, **kw):
+    """Delete legacy files from the specified add-on ids."""
+    log.info(
+        'Disabling legacy files from addons %d-%d [%d].',
+        ids[0], ids[-1], len(ids))
+    qs = Addon.unfiltered.filter(id__in=ids)
+    for addon in qs:
+        with transaction.atomic():
+            # We're dealing with an addon that has the type we care about, and
+            # that we've identified as containing legacy File instances.
+            files = File.objects.filter(
+                is_webextension=False, is_mozilla_signed_extension=False,
+                version__addon=addon)
+            for file_ in files:
+                file_.update(status=amo.STATUS_DISABLED)
+    index_addons.delay(ids)
diff --git a/src/olympia/addons/tests/test_commands.py b/src/olympia/addons/tests/test_commands.py
index fd931973c3..a1a682f5f2 100644
--- a/src/olympia/addons/tests/test_commands.py
+++ b/src/olympia/addons/tests/test_commands.py
@@ -653,3 +653,61 @@ class TestMigrateLegacyDictionariesToWebextension(TestCase):
         # self.addon2 will raise a ValidationError because of the side_effect
         # above, so we should only reindex 1 and 3.
         assert index_addons_mock.call_args[0][0] == [self.addon, self.addon3]
+
+
+class TestDisableLegacyAddons(TestCase):
+    def test_basic(self):
+        # These add-ons should be disabled completely since they only have a
+        # single legacy file.
+        should_be_fully_disabled = [
+            addon_factory(),
+            addon_factory(type=amo.ADDON_LPAPP),
+            addon_factory(type=amo.ADDON_THEME),
+        ]
+
+        # This one has a legacy and a non-legacy version, so only the legacy
+        # File & Version should be disabled.
+        should_have_old_version_disabled = [
+            addon_factory(created=self.days_ago(42),
+                          version_kw={'created': self.days_ago(42)}),
+        ]
+        version_factory(
+            addon=should_have_old_version_disabled[0],
+            file_kw={'is_webextension': True})
+
+        # These should *not* have any File instance disabled, they should be
+        # kept intact.
+        should_be_kept_intact = [
+            addon_factory(file_kw={'is_webextension': True}),
+            addon_factory(file_kw={'is_mozilla_signed_extension': True}),
+            addon_factory(file_kw={'is_mozilla_signed_extension': True,
+                                   'is_webextension': True}),
+            addon_factory(type=amo.ADDON_DICT),
+            addon_factory(type=amo.ADDON_SEARCH),
+        ]
+
+        call_command('process_addons', task='disable_legacy_files')
+
+        for addon in should_be_fully_disabled:
+            addon.reload()
+            assert addon.status == amo.STATUS_NULL  # No public version left.
+            assert addon.current_version is None
+            file_ = addon.versions.all()[0].files.all()[0]
+            assert file_.status == amo.STATUS_DISABLED
+
+        for addon in should_have_old_version_disabled:
+            addon.reload()
+            assert addon.status == amo.STATUS_PUBLIC
+            assert addon.current_version
+            file_ = addon.current_version.files.all()[0]
+            assert file_.status == amo.STATUS_PUBLIC
+            file_ = addon.versions.exclude(
+                pk=addon.current_version.pk)[0].files.all()[0]
+            assert file_.status == amo.STATUS_DISABLED
+
+        for addon in should_be_kept_intact:
+            addon.reload()
+            assert addon.status == amo.STATUS_PUBLIC
+            assert addon.current_version
+            file_ = addon.versions.all()[0].all_files[0]
+            assert file_.status == amo.STATUS_PUBLIC