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LET function disappeared from latest Office 365 build—bug or update issue?

rei Halle 20 Reputation points
2025-08-15T04:38:02.1033333+00:00

I recently updated to the latest Office 365 (Excel for Microsoft 365), and noticed that the LET function isn't recognized anymore—no IntelliSense suggestions, and formulas return a #NAME? error.

There’s no mention of its removal on the official LET support page, nor in any release notes. Previously, I was using LET just fine.

Details:

  • Excel version: 16.1
  • Previously working: Yes, in earlier version/build

Things I’ve checked so far:

  • The Microsoft documentation confirms LET should be available in Excel for Microsoft 365, Excel 2021, and Excel for the web :contentReference[oaicite:1]{index=1}.
  • Some community sources suggest that LET may be unavailable on older builds or if you're on the Semi-Annual Enterprise Channel :contentReference[oaicite:2]{index=2}.
  • But there’s no official changelog or notice indicating LET was removed or deprecated.

So my questions are:

  1. Has the LET function actually been removed or hidden in some builds or channels of Office 365?
  2. Is this a known bug or an issue with channel rollout?
  3. How can I restore LET functionality—e.g., changing update channel, reinstalling, etc.?

Any insight on this would be greatly appreciated!

Microsoft 365 and Office | Excel | For education | MacOS
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Answer accepted by question author

Anonymous
2025-08-15T08:17:58.95+00:00

Hi rei Halle

Welcome to Microsoft Q&A Forum. Thank you for your detailed report and for outlining the troubleshooting steps you’ve already taken. 

Based on my own testing after updating to Excel for Mac version 16.100 (the same version you mentioned), I have not been able to reproduce the issue. The LET function is still available for me, IntelliSense suggestions appear when I type =LET, and formulas using LET return correct results, not a #NAME? error:

User's image

Here are some recommended steps you may consider if you haven't done so:

  • Check your Update Channel if you are on a different channel (such as Semi-Annual Enterprise), I recommend switching to the Current Channel: Learn more about update channelsUser's image
  • Restart your Mac as sometimes, a simple restart after an update can resolve temporary glitches and restore missing features.
  • Signing out of your Microsoft account in Excel and then signing back in can refresh your license and feature set, which may resolve the issue. 
  • Try uninstalling completely and reinstalling Excel app for Mac by downloading version 16.100 directly from the official Microsoft site: Office for Mac update history & downloads
  • Test other modern functions such as XLOOKUP or FILTER besides LET
  • As a temporary workaround, you can use Excel for the web, where the LET function should be available. This can help you continue your work while troubleshooting the desktop issue.
  • Could you please let me know which version of Excel you were using before the update? Before considering a downgrade, please check if that version is stable and still supported. Also, immediately disable Microsoft AutoUpdate (MAU) to prevent automatic updates.

In my opinion, this may not be a widespread bug, but could just be an isolated issue related to update channels, installation, or licensing. Thank you for your patience and for helping us improve the Excel experience.

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".User's imageNote: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

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