Microsoft 365 Alert – Service Degradation – Microsoft 365 Copilot Chat – Users may be unable to view or select specific GPT-based models in Microsoft 365 Copilot chat – RESOLVED

09/07/2026 09:13:00 AM

NHS.net Connect Reference: INC46873892

Microsoft Reference: CW1420563

Issue Status: RESOLVED

Issue Description: Users may be unable to view or select specific GPT-based models in Microsoft 365 Copilot chat.

More info: Affected users may notice that the model selector from Microsoft 365 Copilot chat is missing some GPT options.

The Auto, Quick Response, and Think Deeper options are available and working as expected, while the rest of the Copilot functionality remains unaffected.

Final Update: 09/07/2026 09:14:00 AM– Microsoft’s investigation has confirmed that the disappearance of the GPT 5.5 menu entries is a consequence of GPT-5.5 becoming the default model. As GPT-5.5 becomes the default experience, those nested GPT options are automatically suppressed because they effectively map to the same underlying model now exposed through Auto, Quick Response, and Think Deeper options. This type of selector menu will reappear when additional models become available for selection.
Additionally, we’re exploring options to potentially provide additional guidance through updated documentation and in-product guidance around to which model Auto, Quick Response, and Think Deeper are mapped.

Scope of impact: Impact is specific to some users attempting to view or select specific GPT-based models in Microsoft 365 Copilot chat.

Root cause: An update to the Copilot Chat service that made GPT 5.5 the default model caused the GPT 5.5 menu entries to disappear from the Selector menu.