C:\path\to\project>composer update Loading composer repositories with package information Updating dependencies (including require-dev) Terminate batch job (Y/N)?
When run in verbose mode (-vvv), I found that it was hanging on this URL:
[22.8MB/6.12s] Downloading https://packagist.org/p/provider-stale$1dd2169726dc85ef70959e8ef349c5344fef820de4995ae9ffd1789c19795f7b.json
A quick check showed that the provider document was now 404. Apparently, composer expects you to keep your installation and URL database relatively up-to-date. The solution was relatively simple. Clear the cache so that composer looks for updated URLs. Run:
composer clearcache composer update