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ERROR_APPEXEC_INVALID_HOST_STATE
The AppExec host state is invalid for the request.
ERROR_APPEXEC_INVALID_HOST_STATE is Win32 error 3064 (0xBF8). The host exists, but its current lifecycle or configuration state does not permit the execution request. Public documentation does not define a universal AppExec state machine, so callers must use the producing component’s state query and logs.
States that commonly reject work
- the host is initializing and has not finished registration or resource acquisition
- shutdown, suspension, recovery, migration, or replacement is already in progress
- the host belongs to another app, user, package, session, or generation
- a prior failure left it degraded and accepting only cleanup operations
- the request type is incompatible with the host mode even though the host is otherwise healthy
Host-state evidence
Record the returning API, host ID and generation, authoritative state and transition timestamp, app/package/user/session identity, request type, current registrations, donor/resource availability, shutdown reason, and recent errors. Preserve state names from the owner rather than mapping everything to running/stopped.
Diagnostic sequence
Query the host immediately after 3064 and correlate transition events. Determine whether the state is temporary, terminal, or belongs to a different execution context. Check whether the client dispatched after receiving a stop or invalidation notification.
Create a clean host through the supported path and submit a minimal request. If that works, investigate lifecycle races and stale routing. If it does not, inspect prerequisites and policy before repeatedly recreating hosts.
Recovery and scheduling
Wait for a documented ready transition, reconnect to the current host, or create a replacement as appropriate. Cancel requests bound to a terminal host and replay only work that has not already executed.
Dispatchers should gate requests on authoritative state plus generation, stop queues during transitions, and make completion idempotent. Operators should address repeated invalid states as host stability or orchestration defects, not clear them by indiscriminate reboot.
Difference from condition-not-satisfied
ERROR_APPEXEC_CONDITION_NOT_SATISFIED says a supplied prerequisite evaluated false. Error 3064 says the host’s overall current state cannot support the execution request.
Example
A client sends work while the host is draining for an update. It receives 3064. The dispatcher waits for the replacement host’s ready event and submits a generation-bound request instead of retrying against the draining instance.
References
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