Template References to offline SharePoint On-Prem Server

When documents created from old .dotx templates try to load in SharePoint Online, they still contain an internal reference to the original SharePoint 2016 template library. Since the on-prem server is offline, Office applications attempt to resolve the template path, fail with a 404, and then open the document normally. The delay happens during that lookup process.

This behavior is expected because the template metadata is stored inside the file. Taking the server offline does not remove that reference.

The two practical approaches are:

• Replace the template reference by opening each template, attaching a new template, saving, and re-publishing it. New documents created from that template will no longer point to the offline server.
• Identify affected documents by scanning for URLs in the document properties or by using Office’s “File > Info > Related Documents” metadata. Files that contain embedded template paths pointing to the old SP2016 server will show this delay.

There is no automatic migration mechanism that strips old template URLs, so cleanup must be done either on the templates or by bulk document processing.

lzetaruk​  The issue you described with SP2016 on‑prem is a well‑known behavior. When Word documents are created from templates stored in your old SharePoint 2016 environment, the full path to the template file is embedded in the document. After you shut down the 2016 server, Word still tries to resolve that path each time the document is opened. Because the server no longer exists, Word attempts to connect, times out, and then finally opens the document. That’s why you see the delay.

The resolution is to update or remove those embedded template references. You can do this manually by re‑attaching the document to a valid template in Word (via the Developer tab or Options > Add‑Ins > Templates) or use PowerShell scripts that scan for the AttachedTemplate property and replace the old server path with the new SharePoint Online library path.

To identify affected files, you can either check manually in Word (Developer tab > Document Template) or run a script to flag any documents that still reference http://oldSP2016/.... Files that take unusually long to open are also a strong indicator.

Here are few articles which might help:

• Using Documents after a Server Move (Microsoft Word)
• How to fix slow opening Microsoft Word documents because of invalid network paths
• Updating Many Template References (Microsoft Word)

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