I had the notification in Jira that there were two updates waiting, I went to the plugins screen and updated the UPM, this went ok. I then updated Greenhopper, the progress bar went about 80% of the way across the screen and then 'stuck' after a few minutes I get these messages on the updates screen;
An unexpected error occurred. Please refer to the logs for more information.
and
The system attempted to connect to http://jira.pearson.com/rest/plugins/1.0/pending/3d729b44-f52d-4354-92d7-f0689897e005 to retrieve the status of your operation, but failed. This may indicate a problem with the base URL configuration of your instance. Try refreshing the page to see if the operation completed, and see the UPM documentation for more details about this error.
My Jira instance has now hung and it looks like I'm going to have to reboot to get it working again
Jira 5.0.4 - UPM 2.4.1
Help!