I don't find anything to automatically delete inactive accounts
 

I'm really surprised that there isn't an addon that will automatically delete accounts within specified usergroups after a specified amount of time of no activity at all. When I was running vB 2.3, I had coded my own scripts to run via cron to email any users who haven't been active in over 60 days, 90 days, then one final warning at 120 days with accounts deleted at 130 days.

Unless I'm just blind, I don't see how to do this w/ vB 4.2 automatically. Any ideas?

Nothing?

Why do you want to delete inactive accounts. Just let them be there. People may not be active for sometime and may come back later. This is a good way to reduce activity on your form.

There is no feature to do it automatically, but you can use the "Move / Prune Users" function. There's also a couple of mods that move inactive users to a new usergroup, then all you would have to do would be to periodically delete all users in that group.