Windows sandbox setup checks more and can ask you to reinstall

The sandbox is a restricted environment Claude Code can use to run commands with limited access to your files and network. On Windows, setting it up now does much more than before, when it only checked whether the sandbox was installed and checked trusted certificates.

Setup can now stop with these errors:

• reinstall_required: the sandbox needs to be installed again
• wfp_loopback_mismatch: the firewall rules for local connections on your own machine do not match what is expected
• profile_grant_outdated: the recorded permission to read your user profile is out of date
• profile_exclusion_read_grant: a permission would reach parts of your profile that are meant to stay unreadable

Claude Code checks a recorded permission that lets sandboxed commands read your user profile folder. If there is none, it logs that your profile is not readable to sandboxed commands in this session. It refuses permissions that would reach profile paths that are excluded from reading, unless the dangerouslyAllowReadOfProfileExclusions option is set. The Windows Filtering Platform firewall rules it creates can now allow or block connections to your own machine.