Forum Discussion
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 ...
Have you tried reporting the problem back to Microsoft?
They certainly should be made aware of issues caused by a security update (assuming your diagnosis is correct) and may be able to help. The only time I have had to switch to .xlsb format is when I exceeded an 8k limit on the number of characters forming a single formula, so not that relevant.