BC SharePoint External File Storage view threshold exceeded

The threshold is a SharePoint query limit, not a library-capacity limit, but Business Central’s generated view can fail when its query lacks an indexed filter. Do not manually move files or rename Business Central folders; an unavailable external file can no longer open from its Business Central record. External storage lets administrators create multiple external file accounts and assign an account to an attachment scenario. Therefore, “partition” should mean configuring another supported location for new scenarios or future data, not reorganizing files behind Business Central. First index columns used by the failing view and make its default filter selective. Document the account, base folder, scenario assignment, and company. Before redirecting new attachments, test the account and scenario in a sandbox and confirm old attachments still open. If your release exposes only one scenario assignment, ask Business Central support for a supported migration design; do not implement year-based moves in SharePoint.