I have a 500 GB SSD drive with Windows 10 installed, and a 250 GB SSD drive with Ubuntu 22.04 installed. I use the latter mainly to maintain my privacy; Ubuntu is like my personal computer, with private stuff. I don't really use Windows, but I need it for my job.

My question is: Can Windows access my personal files from the Linux drive? Windows are closed-source, and Microsoft is known for being a privacy nightmare; I'm curious if there's been a case like that.

If that's true, how do you recommend me to protect myself? I'm interested to protect just one directory that contains private stuff. Should I encrypt just that directory alone, or the entire drive? Is it possible (not probable just possible), even that way, for Windows to add malicious stuff to my other drive so it can access my files once decrypted?

  • Sometimes it makes sense to remove a tinfoil hat. Sep 10, 2022 at 11:57

3 Answers 3


It is not impossible for Microsoft to see files on another partition. If found it would be a PR nightmare, hopefully that's enough to stop them from doing it.

not probable, just possible

Just about anything is possible. Windows could install a keylogger into the BIOS which looks for a LUKS partition password and the next time it starts uses it to decrypt the partition. It's possible to do this over an airgap.

But yea, being reasonable about our threats, LUKS partition encryption is probably safest against reasonable attack vectors.

  • Thanks. Would it helped if, before I switch to Windows, I cut that directory to a USB? Seems like a smarter solution that encrypting the whole thing (and perhaps even more secure?). Sep 6, 2022 at 15:23
  • As for anything that's possible, Windows could install a service in Linux which quietly offloads any mounted data. If one dismisses that threat, sure, Windows can't access a drive it never sees.
    – foreverska
    Sep 6, 2022 at 15:28
  • I get your point, but note that this isn't just about Microsoft doing it intentionally. Someone can maliciously get access to Windows (which is easier as I'm not that aware of what I install there), and access my Linux files as well. Transmitting these files in a USB seems a more efficient solution to the same problem, than encrypting it. Sep 6, 2022 at 15:34
  • @BestQualityVacuum you could also create an encrypted LUKS container file. Then mount the container's partition(s) in folder(s) after you log in to your desktop. It could also be done automatically with your profile's keychain/keyring/etc.
    – svin83
    Sep 6, 2022 at 15:38

If you assume simply generally sloppy/user-unfriendly data access: you're fine. Windows can't do anything (e.g. access flash drives or network data) while it's not running, and doesn't know how to parse Linux file systems so it can't read your Ubuntu drive (unless you for some reason formatted it with NTFS, UDF, or a FAT variant rather than Linux defaults like ext4 or btrfs) when it is running. To Windows, the other SSD is a black box of meaningless nonsense.

However, that won't necessarily stand up against an actively malicious piece of software. It's very unlikely that Microsoft starts shipping an ext or btrfs driver with Windows, but it's possible; NT drivers for such file systems do exist, or there's things like WSL (which is disabled by default still) which could mount the other volume if granted access. Similarly it's extremely unlikely that any not-specifically-targeting-you piece of Windows malware is going to bother to include support for Linux file systems, so the other SSD will be meaningless nonsense to them too. But it's not impossible.

Similarly, it's not impossible for Windows (or highly-privileged and advanced malware running on it) to bypass nearly any protection you could put in place. For example, it could easily lift your entire Linux machine into a transparent VM, such that even when you think you've shut down Windows and rebooted into Linux, it's actually still running there, with a lower-level access, able to watch everything. Similarly, as another user mentioned, it might be able to install a keylogger into the machine firmware and can definitely overwrite the Linux bootloader, to introduce a keylogger that captures your disk encryption password. The only real protection is to use a totally separate machine.

On the other hand, you really don't need to be that paranoid about this. Microsoft has no interest in monitoring what you do in Linux; it has reasonably-legit reasons for the monitoring it does in Windows (most of which can be turned off) that mostly wouldn't even apply to Linux and certainly wouldn't be worth the development effort. Not to mention the PR shitstorm when it eventually came out. Windows might be closed source, but that doesn't mean it's an unknowable block box of mystery; there are almost certainly more people monitoring every network packet their Windows machine sends or receives than there are who have read more than 0.1% of the Ubuntu source code, not to mention the thousands of Microsoft employees who work on Windows and related stuff (meaning they do get to see the source code) but do in fact have ethics and sufficiently well-padded bank accounts that most would be willing to object internally to such overreach (which might make the news) and some who would be willing to publicly blow the whistle on it (which would definitely make the news).

  • They do have said they access your files, though, and may choose to share it, as they say (in the tosdr link above). I don't know if that applies legally to other operating systems too. Sep 8, 2022 at 9:13

how do you recommend me to protect myself?

The best two fail safe options are;

  1. Run Windows through a VM rather than have it on a sperate partition or drive.
  2. Have two PC's, one for Windows and one for Linux.

If you encrypt the directory as you suggested, it is an option but not as safe as the tools to decrypt those files are still the same machine rather than sandboxed.

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