{"version":"2.1.309","anchor":"sandbox-mask-file-doctor-message-reworded","canonical_anchor":"sandbox-mask-file-doctor-message-reworded","heading":"Clearer doctor message about leftover sandbox mask files","tier":"notice","area":"Sandbox","scope":"individual","heads_up":false,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.309\/e\/sandbox-mask-file-doctor-message-reworded","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.309","markdown":"### Clearer doctor message about leftover sandbox mask files\n\nThe doctor check now explains that leftover sandbox mask files come from killed sessions or ones that exited mid-command\n\n**What**\n\nThe sandbox is a restricted environment Claude Code can run shell commands in, to limit which files they can change. To block writes to certain paths, called write-deny paths, it places mask files there. Sometimes those files are left behind.\n\nThe doctor diagnostic used to list them as \"Stale sandbox mask files left by a killed session\". It now reads \"Sandbox mask files left behind at write-deny paths\" and explains that a session leaves one when it is killed, or when it exits while a sandboxed command is still running.\n\n**Why**\n\nThe message now gives the real causes of the leftover files, so you have a better idea of where they came from.\n\n- Area: Sandbox\n- Tier: You'll notice\n- Useful: 1\/5\n- Signal: 1\/5\n- Scope: individual\n- Heads-up: no"}