Users complain they miss Linux partitions after installing the Windows 10 Anniversary update. On both social media and Linux related forums users post that the Windows 10 update removed partitions from their system without asking.
https://twitter.com/TheH5S/status/760592120919035906
Seen multiple reports that the Windows 10 Anniversary Update deletes other partitions (containing Linux installs) without asking. :S
— Alan Pope ??????? (@popey) August 3, 2016
The Windows 10 installer busted my partition table but it's okay because I got to use internet recovery and IT'S OLD pic.twitter.com/b7HJ5LSKtr
— laura bananas (@freezydorito) July 29, 2016
Mainly dual-boot users, who have both a Windows and Linux partition on their system, appear to be affected. However there are also some reports of users who store their data on a separate that saw their partition deleted. It's unclear how widespread the issue is, but for affected users it's a scary thing to see their partitions were gone.
Fortunately there is a fix and actual data doesn't seem to be lost. Using a partition manager it's possible to recover the partition and no data should be lost.
This issue doesn't seem to be the only one, users also complain about issues with Microsoft's Virtual Machine software Hyper V. Other users report the installation stopped somewhere in the middle and they were unable to use any Windows recovery tools. They had to resort to reinstalling Windows completely.