At one of our customers we had the error message, that the managed metadata service or the connection is not available. I am not sure, but it may be due to an update we installed a few days earlier.
I read a post which says that the application pool account does not have enough rights to read the registry. The suggestion was to run the following powershell script:
psconfig -cmd secureresources
After i did this, it starts a script similiar to the configuration wizard with three steps and after that we did an issreset. It was working fine after doing this. Hope this helps you some day.The article or information provided here represents completely my own personal view & thought. It is recommended to test the content or scripts of the site in the lab, before making use in the production environment & use it completely at your own risk. The articles, scripts, suggestions or tricks published on the site are provided AS-IS with no warranties or guarantees and confers no rights.