Forum Discussion
Copilot confused by the term "last week"
Hello,
I had several instances where Copilot failed to retrieve information when asked to summarize things about last week. It seems confused about what period 'last week' refers to.
Example of a chat:
Initial Prompt:
What were the Teams messages I received from Thomas last week ?
Copilot said:
Copilot
You received 2 Teams messages from Thomas last week.
The conversation, dated Wednesday the 7th, was about confirming the Copilot training session:
- Thomas: "Olivier, le training copilot se fait bien demain ?"
- You: "Oui, room 225"
- Thomas: "Ok on se retrouve demain"
You said:
What are the dates of last week ?
Copilot said:
Copilot
Last week ran from Monday, May 12 to Sunday, May 18, 2025.
Let me know if you'd like to filter or retrieve anything else from that time frame.
You said:
Then why did you mention messages of May 7th ?
Copilot said:
Copilot
You're absolutely right to question that — thank you for catching it.
May 7th falls outside the range of last week, which was May 12 to May 18, 2025. The messages I referenced earlier were from May 7, so they do not belong to the timeframe you asked about.
Let me recheck for any Teams messages from Thomas specifically within last week’s date range. One moment please.
Thanks for your patience. You received 4 Teams messages from Thomas during last week (May 12–18, 2025) . Here's a summary:
3 Replies
Your findings are fully correct. The underlying LLM does know the exact date only based on your "last week" prompt information. I know – we would expect that the LLM does know the current date as it works when you ask for the current date. Keep in mind with such date-specific questions that it is easier for Copilot to understand your question if you add either the current week or at least the current day we have now. The reason is simple: There is math required for the LLM to get this information, and just "last week" is not enough for the LLM to execute this math. We as humans can do this, as we work in days/weeks/months/years, but LLMs do not.
PeterForster
Not exactly, as you can see from the example I posted, if you ask the question "What are the dates of last week ?", the answer is correct and I did not encounter any occurrence where Copilot would not answer this question properly. However, when the term "last week" is used in a broader query, Copilot fails to retrieve the correct date range.
Microsoft is actually using the https://www.microsoft.com/en-us/microsoft-copilot/for-individuals/do-more-with-ai/ai-for-professional-life/summarize-missed-emails-with-copilot-pro?form=MA13KP so I disagree with your idea that we should not expect Copilot to answer this properly. If LLM can not do this, Microsoft should not advertise it.I completely understand your frustration, especially given that Microsoft has officially announced this feature. I’ve re-checked the current Microsoft 365 Copilot roadmap and noticed that at least some of the mentioned date ranges should now be functional as of June 10, 2025.
While I can’t provide a direct link to the specific section, you can find this information in the Microsoft 365 Copilot Release Notes on Microsoft Learn—just search for the term “week.”:
Release Notes for Microsoft 365 Copilot | Microsoft LearnImportant: This functionality is currently only available in Copilot Chat at https://m365.cloud.microsoft/chat specifically within the “Work” section. I ran a few tests myself, and it seems to be working quite well.
I receive too many emails to verify every entry, but at the very least, it does show me some of my messages. Keep in mind that while prompts like “last week” are now supported, there are still limitations on the number of references that can be returned in a single chat window—so not all messages from last week may be included in the response.
