I've recently had to reinstall Splunk on my server.
It was using an index called "index2", I've since removed that version of Splunk (which I thought would of deleted the index) and installed Splunk v7.
It's worth noting that I had about 10-12 forwarders sending syslog data to my Splunk instance before uninstalling.
Since installing the new Splunk v7 I can only see one available forwarder when selecting "add data"
The odd thing is that when I go to search and reporting and select index="newindex" it generates a whole lot of data and tells me I have 6 hosts contributing data.
This is quite puzzling. The IP address and port of the Splunk instance is exactly the same, so I'm not sure why they don't appear in the forwarder list under 'add data'