Hi @Len Larsen,
You need to Enable "Require Check Out" in SharePoint
- Go to SharePoint Document Library where the files lie in: Navigate to the library where files are stored.
- Open Library Settings: Click the gear icon > Library settings.
- Configure Versioning Settings:
- Under General Settings, select Versioning settings.
- Set Require documents to be checked out before they can be edited? to Yes.
- Save changes.

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