Windows: filesystem limit error (os error 665) flooding Sentry at 6k events

[senamakel]

Sentry: https://sentry.tinyhumans.ai/organizations/tinyhumans/issues/26524/ (TAURI-RUST-QT0)
Impact: 6,050 events · 1 user · error
Seen: first 2026-07-21 · last 2026-07-22
Release / env: openhuman@0.57.40+abddfcbd1b1d / production

Exception: "Impossibile completare l'operazione a causa di un limite del file system (os error 665)"
Culprit: (none)

Analysis: Italian Windows error message: "Cannot complete the operation due to a file system limit." Windows error 665 is ERROR_FILE_SYSTEM_LIMITATION — typically caused by a heavily fragmented file system, a file being written too quickly (exceeding the journal/USN limit), or a filesystem filter driver bottleneck. The single user is generating 3,000+ events/day, suggesting an unthrottled retry loop. The error should be rate-limited and surfaced with a user-friendly message.

Source: Sentry TAURI-RUST-QT0.

[YellowSnnowmann]

Closing as fixed.

PR #5171 (merged 2026-07-24) implemented three-layer suppression for this error:

1. ExpectedErrorKind::WindowsFileSystemLimitation classifier at the emit site in src/core/observability.rs:2319-2333 demotes to warn!
2. A 5-minute rate limiter at src/core/observability.rs:2595-2607 keyed by domain+operation
3. A before_send filter in src/main.rs:119-133 drops any event that slips through

All layers are anchored on the locale-stable (os error 665) suffix, so they work regardless of system locale (the original report was in Italian).