Windows 10 Anniversary Update may affect and even delete other partitions on the same disk, OMGUbuntu is reporting , citing several complaints by users. "Broken boot loaders on an update are one thing but losing data, even entire partitions?" asks the author. Microsoft-centric news blog WindowsReport is corroborating on the report, adding that in some cases, the new OS was not able to detect some partitions . It says (edited):We have reached out to Microsoft for clarification, and will update the post when we hear back from them.