Joomla 1.6 & Plesk 9.5.x Output Buffering

when you try to install Joomla 1.6 on a Plesk 9.5.x you will get the errorĀ in the preisntall check that Output Buffering was On and it’s recommended that it should be Off to do that:

Joomla Administration: Invalid Session 2

If you try to login to the administration of Joomla and you get the error: Invalid Session try the following fix: