Hi i've some troubles with memcached + joomla. I installed and began memcached => joomla options cache type memcache (write memcache options) and session type - memcache too. Save all options and after cann't login to site and administration. By mistake log nothing, after i change cache to database i'm able to login, where's the issue?

What version of Joomla are you currently running and what's the browser / server combination?

I am presuming you've removed the browser cache after making these changes?

Some web servers, especially hosting that is shared, don't cycle as rapidly as we want and I have experienced a lag within the time cache configurations in Joomla are transformed, so when they work...

Avoid using memcached for session cache. Use database or file cache for periods.