Hi,
I just upgraded to stack 1.6. When attempting to start a new project, I received the following error:

******** ERROR MSG **************
Downloading root
Downloading timestamp
Downloading snapshot
Downloading mirrors
Cannot update index (update failed twice)
Verification error: Invalid hash for /01-index.tar.gz
Downloading index
Updating package index Hackage (mirrored at https://s3.amazonaws.com/hackage.fpcomplete.com/) ...
.......

It process stall at the point above.

Thanks,
Ky