Co-authoring lets multiple people edit the same Word, Excel, or PowerPoint file at the same time—changes appear within seconds. It replaces the ritual of emailing `Proposal_v7_final_REAL.docx` around the office.
How it works
Files must live in OneDrive or SharePoint (including Teams-linked libraries). When you open from cloud location:
- Colored presence flags show who is in the file
- Edits sync live; occasional merge prompts appear on rare conflicts
- AutoSave should be on in desktop Office for cloud files
Desktop vs web co-authoring
Web Excel has improved but very large models and some legacy features still favor desktop. For board packs and simple proposals, web is often enough.
Practices that reduce friction
| Do | Avoid |
|---|---|
| Store the file in the team library | Emailing copies that fork history |
| Use @mentions in comments | Hiding sheets critical to others without telling them |
| Agree who owns structure in complex models | Two people restructuring pivot tables simultaneously |
Version history
Cloud files keep version history in OneDrive/SharePoint. When someone breaks a formula, restore a prior version instead of reconstructing from attachments.
External partners
Guests with edit rights can co-author if policies allow. Prefer specific people access over broad anonymous links on sensitive workbooks.
Limits
Some legacy file formats (.xls, old .doc) and encrypted workbooks block co-authoring—convert to modern Office Open XML formats.
Training users on this one workflow often pays back more than another meeting app license.
