Hi,
I have been searching for the a solution on my mac mini (2011) . The indigoserver task "out of the blue" suddenly had over 43 Threads and was consuming quite a lot of cpu.
Naturally I tried to disable all plugins but didn't find the cause of the problem for a long time.
Yesterday I found the cause: My ISP had changed the smtp port on their mailserver. That caused the whole problem.
After I changed indigo's smtp settings to the new port, 30 threads disappeared and the server load dripped to 10%.
Just to let you know, I'm happy again.
Cheers