Using Sitecore 8.2 Update 4, Sitecore Experience Profile is not loading (the spinner keeps on spinning) on our Staging server using a Lucene index. This was working ok last week - it appears to be an intermittent issue.

I've checked the Log and Crawling log - no entries

Memory useage - 73%

CPU useage - increases to ~50% and holds steady

SQL Profile isn't showing a massive load: Mainly calls to the EventQueue table

I can search for individuals by name or email in the Experience Profile, and that is quick.Any suggestions on how to diagnose this appreciated. Please let me know if you require any more info. I have rebuilt the Analytics index using analyticsindexbuilder tool but this had no effect