An update broke something

1. Check whether it is us. The build status page shows every package build, including the ones that were held back. If the last run was held back, the repository has not changed since the one before it, and the cause is elsewhere.
2. Boot the snapshot. With automatic snapshots enabled, the pre-update state is a boot menu entry away. This is the fastest way to get a working system back, and it costs nothing to try.
3. Check what actually changed. /var/log/pacman.log lists every upgraded package with a timestamp, so you can narrow the search to what moved.
4. Read the news. Arch announces every change that needs manual intervention at archlinux.org/news. If an update needed a step you did not take, it is usually there.