Snapshot agent stuck at 48%

We are having to redo a publication/subscription and while running the snapshot agent it stalls at 48% with the message "The process is running and is waiting on a response from the server." Eventually it times out. I increased the timeout, but even after 4 hours it's still stuck at the same place. I can't figure out what it's 'waiting on' or how to get it to progress further. I've tried deleting and recreating the publication from scratch but same results. Anyone have ideas on how I might troubleshoot it to figure out what the issue is?