The data loss issue in 1809 was the result of Microsoft intentionally writing and deploying code with the specific purpose of deleting people's documents direct

The data loss issue in 1809 was the result of Microsoft intentionally writing and deploying code with the specific purpose of deleting people's documents directories and everything contained within them. The way to avoid this was not to program Windows updates to delete people's documents. (For anyone who doesn't know the context: Windows has the ability to redirect the various documents, music, etc directories away from their default locations. Some genius at Microsoft decided that any data left in the original location after such a move was junk and got a Windows 10 update to delete it. Unfortunately, Microsoft's own OneDrive software, which was bundled with and heavily promoted by Windows 10, intentionally redirected some of these folders without moving the contents in older versions and also often failed part-way through leaving some files behind in newer versions which promised to move the existing documents too. So a whole bunch of people who'd clicked Yes when Windows 10 pestered them to put their documents in OneDrive found that not only did it fail to do that, they got all their non-cloud-backed-up documents deleted a few Windows updates down the line. Making matters worse, some of the members of their crowdsourced beta-testing program had apparently hit this problem and warned them that the update was deleting people's documents, and Microsoft just ignored it and went ahead with the update anyway.)