The first thing to try is deleting all files in the core/cache directory and using incognito or private mode in your browser.
discuss.answer
Thanks for feedback, but this didn't solve the problem.
It turns out to be in the database.
When moving a site to localhost the following entries must be adapted:
modx_system_settings
--> site_name
--> session_cookie_domain
Also all hard coded links in 'modx_context_setting' (I'm using Babel for multi-lingual site)
The 'moving-your-site-to-a-new-server' document should be expanded to give a hint in the 'Update your Database' section.
