diff --git a/git_cl.py b/git_cl.py
index e88bfc6e76..0417eb63d0 100755
--- a/git_cl.py
+++ b/git_cl.py
@@ -3902,7 +3902,7 @@ def CMDcreds_check(parser, args):
     """Checks credentials and suggests changes."""
     _, _ = parser.parse_args(args)
 
-    if newauth.Enabled():
+    if newauth.EnabledInConfig():
         cl = Changelist()
         try:
             remote_url = cl.GetRemoteUrl()
diff --git a/newauth.py b/newauth.py
index def10f9901..ac18c25ddc 100644
--- a/newauth.py
+++ b/newauth.py
@@ -6,12 +6,53 @@
 from __future__ import annotations
 
 import os
+import sys
 
 import scm
 
 
 def Enabled() -> bool:
     """Returns True if new auth stack is enabled."""
+    if not EnabledInConfig():
+        return False
+    if _HasGitcookies():
+        _PrintGitcookiesWarning()
+        return False
+    return True
+
+
+def _HasGitcookies() -> bool:
+    """Returns True if user has gitcookies file."""
+    return os.path.exists(os.path.expanduser('~/.gitcookies'))
+
+
+_warning_printed = False
+
+
+def _PrintGitcookiesWarning() -> None:
+    global _warning_printed
+    if _warning_printed:
+        return
+    _warning_printed = True
+    sys.stderr.write(f'''
+!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Warning !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+depot_tools will soon stop using the .gitcookies file for authentication.
+
+To silence this warning, please move or delete {os.path.expanduser('~/.gitcookies')},
+or you can run `git cl creds-check` which will help you fix this.
+
+If you encounter any issues, please report them using:
+https://issues.chromium.org/issues/new?component=1456702&template=2076315
+--------------------------------------------------------------------------------
+
+''')
+
+
+def EnabledInConfig() -> bool:
+    """Returns True if new auth stack is enabled.
+
+    Directly checks config and doesn't do gitcookie check.
+    """
     return scm.GIT.GetConfig(os.getcwd(),
                              'depot-tools.usenewauthstack') in ('yes', 'on',
                                                                 'true', '1')