Hi Nick,
Are you sure your client is using SQL Server? Could they be using PostGIS instead? From an internet search the error message seems to be common to PostGIS.
If SQL Server, you can view the check constraints in SSMS:

In your client's case, the check constraint is named "enforce_geotype_wkb_geometry". You are probably on the right track in guessing that the multipoints have something to do with it. Perhaps the constraint could be modified to accept multipoint geometries.
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James Nolet
Dooley Mitchell & Morrison Pty Ltd
Mentone, VIC, Australia
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Original Message:
Sent: 07-19-2021 07:21
From: Nick Hall
Subject: Data in SQL server
Hi,
Client has data in SQL server that they can successfully connect too via ODBC and view, etc. One particular dataset is giving them issues. It opens OK but any save of edits returns the following error.
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Nick Hall
Mapchester LTD
Manchester
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