The sandbox is a fenced-off environment that limits which files and network addresses commands run by Claude Code can reach. On Windows, Claude Code now writes the sandbox's deny rules (the list of paths commands may not touch) itself, through a built-in native command. It also renews them while it runs. If renewal fails, Claude Code stops with an error and reports that the rules were not renewed.
To switch this off, set the environment variable CLAUDE_CODE_SANDBOX_LEAVE_DENIES_TO_SRT_WIN. Claude Code checks it at startup and, when it is set, leaves the deny rules to the sandbox runtime, srt-win, as before.
Claude Code also expands wildcard patterns in deny and allow paths, and it now takes symbolic links (shortcuts that point to another file or folder) into account when it does.
This changes how Windows sandbox file protections are enforced. If the new behaviour causes problems, the environment variable lets you go back to the old one.