It seems easy but why is it different from other patches and it requires a phone call?

The reason we make some patches available without a phone call is that those patches have gone through more rigorous testing, in a larger variety of scenarios and topologies, to reduce the risk of regressions. Hotfixes that require a phone call have been heavily tested, but in a more limited set of scenarios and topologies, which is why we recommend calling for them only if you are hitting the problem described in the hotfix's KB article.

There should be a way to get hotfixes without having to waste all tha time on the phone. If you're a volume licensing customer or have SA on your MS products, you should be able to go to a website and download whatever hotfixes you need.

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