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djflobo's avatar
djflobo
Copper Contributor
Apr 03, 2026

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 ...
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Patrick2788's avatar
Patrick2788
Silver Contributor
Apr 06, 2026

 

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.

Yes, this is worth a try. If you can open the file without a repair notice, you might be home free.

My recommendation:

  1. Open the file in Safe mode on a PC
  2. File | Save As to create a new workbook with a different name
  3. Test on the Mac

The reasoning:

I work out of an AFE module daily for hours. I've gotten pretty good at finding ways to bonk Excel through stress testing.  One thing Excel does not like doing is repeatedly calculating large spill arrays and re-sizing large spill areas. It's one way to get the workbook stuck where it doesn't want to even do the simplest calculations.  I don't know if your workbook does this but it's worth a try.  It's my understanding Excel will re-constitute the calculation chain when a workbook is re-named.