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E_CHANGED_STATE
Concurrent work changed the object state
E_CHANGED_STATE is HRESULT 2147483660 (0x8000000C) from winerror.h. The documented description is “A concurrent or interleaved operation changed the state of the object, invalidating this operation.” The relevant context is the Windows Runtime metadata, object lifetime, asynchronous operation, activation, and apartment model.
Where it is encountered
- C++/WinRT, WRL, .NET projections, or native WinRT ABI calls.
- Runtime-class activation, WinMD reflection, asynchronous objects, observable state, or view lifecycle.
- Cross-thread and cross-apartment handoff between UI, ASTA, STA, MTA, broker, and background work.
The immediate focus is an operation whose preconditions were valid when it began but were invalidated by an interleaved mutation, callback, or asynchronous completion.
What to verify
Verify that the caller can identify the state generation that changed and can safely rebuild the operation from a fresh snapshot without duplicating effects. Validate this condition using the owning API state, not an inferred UI symptom.
Difference from nearby HRESULTs
It reports invalidation by another transition; E_ILLEGAL_STATE_CHANGE reports that the requested transition itself is forbidden.
Correct handling and recovery
Discard stale outputs, reacquire current state, and retry only the idempotent portion. Serialize mutations or add generation checks when the same race can recur.
Practical scenario
A settings page validates a draft while another window commits a newer version. The save detects the version mismatch, reloads the latest document, and asks the user to reconcile changes.
References
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