About one month ago, it was in the news that some dual-boot users found their Linux partition deleted after upgrading to Windows 10 anniversary.

I have a Windows partition that I haven't touched since then (for other reasons); is it considered safe to update now, or should I leave it in the freezer for a while again?

closed as off-topic by edwinksl, xangua, Eric Carvalho, Kevin Bowen, TheWanderer Sep 1 '16 at 14:35

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "This is not about Ubuntu. Questions about other Linux distributions can be asked on Unix & Linux, those about Windows on Super User, those about Apple products on Ask Different and generic programming questions on Stack Overflow." – edwinksl, xangua, Eric Carvalho, TheWanderer
If this question can be reworded to fit the rules in the help center, please edit the question.

  • You will have to ask Microsoft about this. This is not something related to Ubuntu. – edwinksl Aug 31 '16 at 19:43
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    @edwinksl I 1/2 agree with you. I think this is still on-topic here. I mean, for crying out loud, we have a Q&A on this site for how to remove Ubuntu and put Windows back on... I think we can let this question slide. – Android Dev Aug 31 '16 at 19:46
  • @edwinksl I understand that technically this is a Windows bug, but I thought dual boot issues were on-topic here. There are 9.560 questions tagged dual-boot here, at least. – Federico Poloni Aug 31 '16 at 19:47
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    @CristianaNicolae There is an option to flag for "moderation attention", which I believe is more appropriate in these cases, as flags for closure could trigger spam warnings. In any case, I have no objection to migration to Super User, if that is the consensus. – Federico Poloni Aug 31 '16 at 22:06
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    I was asked if this was a good fit for superuser. While I wouldn't modhammer it, the question seems hugely speculative over whether this is an issue - its linking a slashdot post linking omgubuntu, citing a person who heard of people who lost data. I'm disinclined to support a move to SU - while it feels borderline unclear. The major windows 10 updates are essentially an OS reinstall/upgrade in place, and one really ought to back up the entire drive(s) before doing this. – Journeyman Geek Sep 1 '16 at 11:24

The Anniversary Update for Windows 10 recently installed on my development machine and the dual-boot grub menu still loaded both Linux and Win 10. I suspect that some users have seen the MBR over-written by Windows rather than their Linux partition actually being deleted, so that all that was likely required was to re-install grub. After all, Windows says it can't "see" Linux partitions; they are just some hole in the disk as far as Redmond is concerned! {grin}

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    The notorious Windows Anniversary Update can do two nasties. It can overwrite GRUB with a standard Windows Boot Manager. And, there have been instances of it turning Ubuntu/Linux partitions into UNALLOCATED space! Ouch. Cheers, Al – heynnema Aug 31 '16 at 21:37
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    Windows can be so jealous! – Cristiana Nicolae Aug 31 '16 at 22:19

I just updated three dual-boot machines, two UEFI/gpt partitioned, and one legacy/MSDOS partitioned by downloading the Windows anniversary 10 update ISO and running it locally. All three updates proceeded without problems, no Ubuntu partitions were touched, and the grub bootloaders were not affected. That said, backups are still a really good idea -- bad things have been reported by others.

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