Getting started in Excel Labs Custom Modules (missing "publish" step)
First-time poster — please be gentle! Context Excel for Mac I have a large library of LAMBDA formulas and wanted to manage them using Excel Labs In particular, I wanted to organise formulas into custom Modules Issue How to actually activate functions defined in custom Modules in Excel Labs I recently discovered Excel Labs and was very excited to use it to manage and structure a large library of LAMBDA formulas. My goal was straightforward: create custom Modules to organise formulas by purpose, and then use those formulas in the workbook. However, it took several hours of experimentation and debugging — even to get a trivial example like: ABC() = 12 to work when defined in a custom Module. The missing piece (which Copilot, Google searches, and the README all missed) is this: Functions defined in custom Excel Labs Modules are inert until the module is imported into the special Workbook module. Until that import step occurs, functions in custom Modules: do not appear in Excel Labs → Names do not appear in Formulas → Name Manager are not callable from the grid According to Copilot this behaviour is not currently documented, and the UI strongly suggests that custom Modules are “active” by default — which they are not. Working workflow (for others who hit the same issue) This is the workflow that finally made things work for me (possibly sub‑optimal, but reliable): Create and maintain functions in custom modules (e.g. Transformations) Explicitly import the required functions into the Workbook module, e.g.: TransformAtoB = Transformations.TransformAtoB Workbook module now publishes to: Excel Labs → Names Formulas → Name Manager This makes conceptual sense — maintain a large structured library of formulas (or import libraries from GitHub), only activate the formulas required by a particular workbook. But without documentation, it’s very easy to assume custom Modules are active by default. Why I’m posting this When I finally asked Copilot “Why didn’t you say this up front?”, the answer was essentially: This publish step is not documented in the README or the UI, and users are easily led to assume Modules are active by default. So I’m posting here to save others from repeating the same debugging journey. Documentation request It would help enormously if the documentation (README / FAQ) stated explicitly that: Custom Modules are source-only Importing into the Workbook module is the publish step Only the Workbook module is wired to Name Manager and the Excel grid Even a short note would remove a major stumbling block for new users. I’m not a GitHub user, otherwise I would also raise this there — if someone from the community is able to mirror this feedback on GitHub, that would be much appreciated.Excel says two numbers are not equal
Column A are numbers typed into the cells. Column B, the numbers in B1 to B3 are also typed in. Cell B4 is SUM(b1:b3) C4 is =B4=A4 Can someone please explain why excel is saying the two numbers in A4 & B4 are not equal. I understand about using rounding or truncation with large calculations but I've never seen anything like this on such a simple calculation. I've tried this on a new spreadsheet and the results are the same. I am using Excel Version 16.109 (26033013) on a Mac. Thank you for your help.
Excel repair strips all formulas from large .xlsm after March 2026 security update (KB5002849)
Hi everyone, I'm a master's student at Karolinska Institutet in Stockholm. My thesis is a health economic cost-effectiveness model built entirely in Excel — a gender-neutral static Markov cohort model with 34 worksheets. The file has become completely unusable after what I believe is the March 2026 security update, and I'm running out of options. The file: - .xlsm, ~46.5 MB compressed, ~370 MB uncompressed XML - 34 worksheets, four of which are 73–92 MB each (Markov trace sheets) - ~65,000 formulas, ~33,500 shared formulas - Heavy use of LET, LAMBDA, XLOOKUP, XMATCH, CHOOSECOLS, TAKE, MAP, SWITCH - 771 defined names including ~147 hidden _xlpm.* LET/LAMBDA variable placeholders - Stored on OneDrive via KI SharePoint, 34,000+ AutoSave revisions - Contains VBA (vbaProject.bin) The problem: Every time I open the file — on Excel for Mac or Excel Online — the repair engine triggers and strips ALL formulas from every sheet, replacing them with cached values. The file shrinks from ~46.5 MB to ~26 MB. Clicking "No" on the repair dialog just closes the file. There is no way to bypass the repair. What I've verified: - Extracted the .xlsm as a ZIP and confirmed all formulas (<f> tags) are fully intact in the raw XML - Libr€Office Calc can read the formulas but cannot execute them (Err:508 — no LET/LAMBDA support) - Removed 158 broken named ranges (#REF! and #NAME? entries) from workbook.xml and rebuilt the archive — repair engine still strips all formulas - The issue reproduces on every OneDrive version history copy (up until I largely used LET formulas in my sheets - but there is still 1,5months of changes lost) - The issue reproduces on both Excel for Mac and Excel Online Suspected cause: The March 10, 2026 security update (KB5002849) patched CVE-2026-26108, a heap overflow in Excel's file parsing during loading. The same patch was applied to Office Online Server (KB5002846). I believe the tightened parsing now rejects or flags my file's large XML structures as potentially malicious, triggering the repair engine to strip all formulas. This is consistent with: - The known _xlfn. namespace bug on Excel for Mac (reported by multiple users on Microsoft Q&A since late 2024) - The timing - the file was working before this update flawlessly up until March 16th - The fact that Excel Online is also affected (same server-side patch) My questions to the community: 1. Has anyone else experienced formula stripping on large workbooks after the March 2026 update? 2. Is there a way to bypass the repair engine on Mac, or roll back the specific security patch without downgrading all of Office? 3. Would opening this file on Windows Excel (pre-patch or current) preserve the formulas? If anyone with a Windows PC would be willing to try opening and re-saving this file, I would be incredibly grateful. 4. Is there now effectively a size/complexity ceiling for Excel workbooks that makes models like this unviable? If so - should I be migrating this to another environment (R, Python, etc.) going forward? This file represents six months of thesis work. The formulas are all there in the XML. I just need Excel to stop destroying them on open. Any help, pointers, or similar experiences would be hugely appreciated. Thank you, Florian Boschek
File always corrupt
Anyone have the same problem with me? I use microsoft excel 365 on my mac. At the beginning everything alright, until i use formula and then save the file. When i want to re-open the file, the messagebox showed up "we found something wrong in your content...". It gives 2 option, yes and no. If i click no, the file wont open. If i click yes, the file open, the excel do the recovery, the file open but end up with all the formulas is gone, deleted by excel and just left the value. What should i do? Do the file can still be fixed?
How to keep the result of the formula from appearing down the column before a number is added
I wish to produce a Teams running score sheet for lawn bowls. When each team (rink) has finished their end the score for either the H or A team is entered. When the next end is finished again the score is entered for the winning team. I am using an IF function in each of the coloured cells: =IF(B13="",C12,B13+C12) This works well, however the result of C?? runs down the entire column as cells in column B are blank waiting for the scores to be added. How can I fix this so the scores show for the rows only and not the entire column. Formula for the TOTALS column is =C10+G10+K10
mac Excel: can't select form Group Box
Hi, I'm using Excel 16.107 on a Mac. I have Developer mode enabled and placed form elements, including group boxes. What I've found is if I delete the text label for a group box, the group box then becomes impossible to select -- there's nothing to click on with my pointer. See attached. Any attempt merely selects the cell, not the group box. How can I select group boxes like this, so that I can delete it or edit its properties?unpivot data and handle merged cells without using Power Query (Unpivot_Toolkit)
Hey, guys!! I’ve been working on a set of functional Excel Lambdas to solve a common headache: transforming "Wide" human-readable data into "Long" database formats without having to open Power Query every time. =UNPIVOT_PLUS(table, [no_of_cols], [no_of_headers], [attribute_names], [value_name], [remove_errors], [remove_blanks],[pad_blanks_with],[pad_errors_with]) Don’t worry about the full list, most use cases only require 5 arguments. I've included a table of default values at the end. Merged Cell Support: Automatically handles fill-down/fill-right logic for merged headers/columns. Bonus Helper: SPLIT_INJECT =SPLIT_INJECT(array, target_indices, delimiter, [ignore_empty], [match_mode], [pad_with]) It targets specific columns, splits them by a delimiter (like TEXTSPLIT), and expands the entire table horizontally while keeping all other columns perfectly stable. Optional arguments match TEXTSPLIT defaults. Feel free to tear this apart or adapt it for your own edge cases. I’d love to hear how you end up using it! You can grab both functions from my GitHub Gist https://gist.github.com/Medohh2120/f8553c149684e39bb499249e39f01017 File with use cases https://1drv.ms/x/c/6c310c8fd1669a94/IQCscpo3yh7jR5XdGZe2AQGyAf4-vCd8K6BvLZQgrP2V8Oo?e=gPdbOd Argument Description Default Behavior table The array or range of data to unpivot. Required argument (no default) [no_of_cols] Fixed left columns to keep as identifiers. 1 [no_of_headers] Top rows used as headers, handling merged cells. 1 [attribute_names] Header name for the unpivoted attributes . "Attribute" [value_name] Header name for the unpivoted values. "Value" [remove_errors] Excludes grid rows with formula errors. FALSE [remove_blanks] Removes grid empty cells and empty strings. TRUE [pad_blanks_with] Value to substitute for empty cells. Leaves cell blank [pad_errors_with] Value to substitute for errors. Leaves error as-is
