Buildbarn CAS NOT_FOUND
A requested digest is absent from the content-addressable store visible to the requesting component. The digest may never have arrived, may have been evicted, or may be inaccessible through the active storage path.
Common causes
- An input upload did not complete before execution
- Storage eviction removed a blob still referenced elsewhere
- Replicas or storage tiers are inconsistent
- A proxy or routing configuration points clients and workers at different stores
What to check
- Identify the missing digest and the component requesting it
- Trace the corresponding upload or ByteStream write
- Check storage eviction and replication health
- Confirm clients, schedulers, and workers resolve the intended CAS endpoint
Primary sources
Use these references to confirm protocol and version-specific behavior.
Investigate with build-level evidence
Hermetiq correlates Bazel actions, cache behavior, Buildbarn infrastructure, and remote-execution timing so teams can move from a status code to the build and system behavior behind it.
Technical review: July 20, 2026 · Verify flags and behavior against the Bazel and Buildbarn versions deployed in your environment.