What does HRESULT 0x00040170 (CACHE_S_FORMATETC_NOTSUPPORTED) mean?

CACHE_S_FORMATETC_NOTSUPPORTED

OLE cache skipped an unsupported presentation format

CACHE_S_FORMATETC_NOTSUPPORTED is HRESULT 262512 (0x00040170) from winerror.h. The documented description is “FORMATETC not supported.” The high-order severity bit is clear, so this is a success result, but it carries more information than plain S_OK.

The cache operation completed with information that the requested FORMATETC is not supported for caching.

State to verify

The central question is whether other requested cache entries and the object itself may remain usable even though this particular format was not accepted.

A reliable interpretation of this result names the exact method contract, the object instance, and the outputs that remain valid. This prevents a success-with-information result from being promoted to full success or demoted to a generic error.

Where the result is encountered

• This result can appear in IOleCache::Cache requests; record the producing interface and method.
• It can appear in embedded-object presentation caching; record the producing interface and method.
• It can appear in containers preparing offline display data for several aspects or media types; record the producing interface and method.

Evidence to preserve

• Preserve the rejected FORMATETC fields.
• Preserve supported formats enumerated by the data object.
• Preserve cache connection identifier output.
• Preserve ADVF flags and update policy.
• Preserve whether a fallback presentation was cached.

Diagnostic sequence

• Capture the raw HRESULT 0x00040170 immediately after the returning method and record whether the caller used SUCCEEDED, FAILED, equality testing, or exception translation.
• Verify the method-specific state: other requested cache entries and the object itself may remain usable even though this particular format was not accepted.

Correct handling, retry, and recovery

Choose a supported presentation format or continue without that cache entry when live rendering is acceptable. Do not assume the source data format itself is invalid.

Practical validation scenario

A container asks an object to cache a custom device-dependent format for offline thumbnails. The object declines that FORMATETC but accepts a metafile fallback, which the container verifies after closing the server.

Difference from nearby HRESULT values

DATA_S_SAMEFORMATETC reports equivalence; it reports that the requested cache representation cannot be created.

Developer and administrator guidance

References

• Microsoft: COM cache status codes
• Microsoft: IOleCache::Cache
• Microsoft: IOleCache