This is the kind of bug that makes you question the tools you rely on every day. A user on MacOS Excel reports that opening the VBA editor locks every other open file, and the only way forward is to kill the process and risk losing conditional formatting, formulas, and even entire tables. The repair logs tell the story: "Removed Feature: Conditional formatting" repeated across sheets, "Removed Records: Formula" and "Table" scattered through the workbook. That is not a glitch. That is a systematic failure of a product that positions itself as enterprise-grade.
What this means for anyone who depends on macros is practical and immediate. You cannot trust Excel to keep your work safe when you need to edit VBA. The moment you open that editor, you are gambling. If you have a complex file with conditional formatting across twenty sheets, shared formulas, and calculated tables, the repair process will strip those out. Your formulas become #NAME errors. Your tables vanish. Your conditional formatting is gone. And the file that triggered the problem becomes unopenable until you restart Excel, at which point you discover the damage has already been done. This is not a corner case. The user reports it happens with every file, regardless of size or complexity.
The root cause appears to be a lock contention issue in the MacOS version of Excel. When the VBA editor opens, it claims an exclusive hold on the Excel process, preventing any other file from being accessed. That alone is frustrating. But the real damage comes when you force-quit: the files that were open during the lock are marked as needing repair, and the repair algorithm removes features it considers problematic rather than actually fixing them. Conditional formatting and formulas are treated as disposable. The user's repair log shows over thirty individual removals across multiple sheets. That is not a repair. That is data loss wearing a different name.
If you are running Excel 16.106.2 on MacOS and rely on macros, you need a different approach. Do not open the VBA editor while other files are open. Save everything first. Better yet, consider whether a tool that treats your formulas as optional is the right foundation for your workflow. The spreadsheet landscape is shifting, and incidents like this are not just annoyances. They are signals that the old guard is no longer designed for the way people actually work. You deserve tools that do not punish you for trying to improve them.