My system guys do something in SQL server yesterday because of the sql space was full.
They just said delete some history.
The Term store management in settings shows error like this :
The Managed Metadata Service or Connection is currently not available. The Application Pool or Managed Metadata Web Service may not have been started. Please Contact your Administrator.
But the service is already running so tried to restart the service and pool in IIS. but not working still.
I checked the log files and there is taxonomy error like this :
Failed to get term store for proxy ‘Managed Metadata Service’.
Exception: System.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary.
So search the google and found good solution in ARE’s blog.
1. Central Administraion -> Manage Service Applications -> Managed Metadata Service : Properties button
2. Change the new database name for temporaliy and click ok to save current setting.
3. Change the database name for previous original DB name for managed metadata service.
if you check the managed metadata service it will show only default metadata. your previous termset is not showing yet.
4. Set Term Store Administrators and then the previous group and termset will be showing.