diff --git a/fdroidserver/update.py b/fdroidserver/update.py
index 57e7e4b7..5872f96f 100644
--- a/fdroidserver/update.py
+++ b/fdroidserver/update.py
@@ -2315,7 +2315,13 @@ def main():
                                            options.use_date_from_apk)
     cachechanged = cachechanged or fcachechanged
     apks += files
+    appid_has_apks = set()
+    appid_has_repo_files = set()
     for apk in apks:
+        if apk['apkName'].endswith('.apk'):
+            appid_has_apks.add(apk['packageName'])
+        else:
+            appid_has_repo_files.add(apk['packageName'])
         if apk['packageName'] not in apps:
             if options.create_metadata:
                 create_metadata_from_template(apk)
@@ -2334,6 +2340,15 @@ def main():
                 else:
                     logging.warning(msg + '\n\t' + _('Use `fdroid update -c` to create it.'))
 
+    mismatch_errors = ''
+    for appid in appid_has_apks:
+        if appid in appid_has_repo_files:
+            appid_files = ', '.join(glob.glob(os.path.join('repo', appid + '_[0-9]*.*')))
+            mismatch_errors += (_('{appid} has both APKs and files: {files}')
+                                .format(appid=appid, files=appid_files)) + '\n'
+    if mismatch_errors:
+        raise FDroidException(mismatch_errors)
+
     # Scan the archive repo for apks as well
     if len(repodirs) > 1:
         archapks, cc = process_apks(apkcache, repodirs[1], knownapks, options.use_date_from_apk)
diff --git a/tests/index.TestCase b/tests/index.TestCase
index 16885dbf..3753f0b4 100755
--- a/tests/index.TestCase
+++ b/tests/index.TestCase
@@ -354,6 +354,15 @@ class IndexTest(unittest.TestCase):
                               'https://gitlab.com/group/project/-/raw/master/fdroid'],
                              fdroidserver.index.get_mirror_service_urls(url))
 
+    def test_v1_sort_packages_with_invalid(self):
+        i = [{'packageName': 'org.smssecure.smssecure',
+              'apkName': 'smssecure-custom.fake',
+              'signer': None,
+              'versionCode': 11111}]
+
+        fdroidserver.index.v1_sort_packages(
+            i, fdroidserver.common.load_stats_fdroid_signing_key_fingerprints())
+
 
 if __name__ == "__main__":
     os.chdir(os.path.dirname(__file__))