Working on a .Net 3.5 client app, I am stuck using the lesser evil of Linq2SQL (compared to the awefulness that is EntityFramework 1).
Updating data on a column results in a ChangeConflictException : “Row not found or changed”. The usual culprit of the DBML differing even slightly from the actual DB model was not to blame, and the concurrency was not either, since the processing took a few milliseconds at worst, on a local DB.
It actually was a trigger updating the “updated_at” column. In the DBML editor, setting the column to “check update : never” and “automatic synchronization : always” solved the problem.