Among Windows 10 Anniversary Update's more obnoxious bugs is one that erroneously reports certain drives (actually, partitions) are in RAW format and can't be accessed from inside Win10.
When Win10 encounters a RAW-formatted partition, it encourages you to format the partition, thereby wiping out all the data on it. Of course, if the bad partition contains perfectly usable files -- indeed, in most cases, it includes files that are readily accessible in Windows 10 Fall Update -- you may get suckered in, reformat the partition, and lose all of your data.
I talked about this, uh, feature of Windows 10 Anniversary Update on Aug. 4, two days after the Anniversary Update/version 1607/build 14393 hit. It's one of the main reasons why installing Anniversary Update is a particularly poor choice.
On Aug. 16, two weeks after the bug was unleashed, Microsoft employee maheshrd stated on Reddit:
We are actively building and testing an update to fix this issue into Windows. We'll deploy the update via Windows Update as soon as that process is finished, restoring access to your files on the affected drives. In all of the cases that we have diagnosed, files were safely intact on the drives – so please, don't reformat. You can also access your files by connecting the affected drive to a different machine (not running Anniversary Update), if that is an option for you. If waiting for an update is not an option, then rolling back will also restore access to your files. For up to 10 days after installing the Anniversary Update, you have the ability to "go back" or return to the previous build. To uninstall the Anniversary Update: 1. Open the Settings app. 2. Select Update & security and then the Recovery tab. 3. Under "Go back to an earlier build", click the Get started button and follow the instructions.
(Note: If more than 10 days have elapsed since installing the Anniversary Update or the "Go back" option is otherwise not available; we ask for your patience until a patch can be released)
A Reddit post earlier today from maheshrd implies that the problem still hasn't been fixed in today's cumulative update for Windows 10 Anniversary Update.
Folks, we are still working through all the issues reported. Believe me, the team is working hard in getting the fix out to everyone's machines. I request your continued patience during this time and thanks for your help and support.
Confusingly, Microsoft employee and forum moderator Sharath Srinivasa posted this plan of action the Microsoft Answers forum, dated Sep. 8:
Microsoft is planning to release a fix to address the majority of the misidentified partitions in an upcoming Windows Update.
As part of the Windows Insider Program, users can sign up to receive Windows 10 updates early in order to provide feedback. If you are interested in becoming a Windows Insider, first go to the Windows Insider website and register your Microsoft Account. Then in Windows 10, open Settings, Update and Security and click on Windows Insider Program. You will be asked to associate your Microsoft Account. You can then click the Get Start button. You may be asked to reboot your PC for the change to take effect.
The default setting after joining the Windows Insider Program is to receive early access to updates for Windows 10, Microsoft applications and drivers with minimal risk to your device. It can take a day or more for the change to begin delivering these accelerated updates.
If you follow Srinivasa's instructions to the letter, you end up in the Release Preview Ring, which is where Microsoft sends you patches for the Anniversary Update before they're released to the world at large. But there hasn't been a Release Preview Ring release since Sep. 8. In fact, there hasn't been a Release Preview Ring release for 1607 in many weeks.
I have no idea what's going on. Perhaps someone at Microsoft can enlighten us. At any rate, until Microsoft fixes this and a handful of additional bugs in Win10 Anniversary Update, I strongly recommend that you block it.
Mary Jo Foley posted an article in ZDNet this morning that says the Anniversary Update rollout may not be done until November. Perhaps Microsoft will get the major bugs in Anniversary Update fixed by then.