[BUG] When saving xlsm files using VBA, openpyxl destroys all cell formulas (replacing them with cached values).

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Claude Code did today:
▎ When saving xlsm files using VBA, openpyxl destroys all cell formulas (replacing them with cached values).
▎ What happened in this session: all formulas in PoetrySlamAuswertungen.xlsm were corrupted.

What Should Happen?

So that was my mistake – I used openpyxl even though it isn’t suitable for xlsm files with VBA.
Restoring the formulas then took you about 5 hours. I’m sorry about that.

Error Messages/Logs

Steps to Reproduce

• Analysis sheet restored from backup (Copy-0414-14:11.xlsm) (rows 1–115)
• External file references cleaned up using Copy() via PowerShell

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Claude Code 2.1.109

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

WSL (Windows Subsystem for Linux)

Additional Information

_No response_