This Windows feature can wreck your Linux files, and most dual-boot users miss it

Dual-booting Linux is easier than you think, and comes with performance benefits virtual machines can’t match. However, Linux and Windows treat storage partitions differently, which can lead to problems.

Specifically, a feature built into Windows can mess up your Linux files. And if you’re not careful, it can lead to anything from a couple of lost files to entire directories being corrupted.

Fast Startup isn’t really shutting Windows down

Hybrid hibernation keeps parts of your system session alive

Microsoft introduced Fast Startup (also called Hybrid Boot) back in Windows 8, and it’s been around in every Windows version since, quietly enabled by default and helping your system boot faster. It works similarly to the hibernate feature you still have on Windows, saving your current OS state to the storage drive before turning the system off so it can resume where you left off when you boot it next.

So instead of doing a full shutdown, Windows logs off your user session, then saves the kernel and system session state into a hibernation file called hiberfil.sys. When you boot back up, Windows loads that file instead of initializing the entire OS from scratch. This results in a system that boots up significantly faster, especially if you still have older and slower hard disk drives.

It works as advertised, but it does have its problems. For starters, if you have an SSD (as is the case with most modern computers), Fast Startup isn’t going to make much of a difference. Secondly, the fact that you’re essentially resuming a previous Windows session means you’re not truly shutting down your PC, meaning you have to use the restart option instead if you made a change that needs a restart to take effect. This is one of the reasons why you should turn off Windows Fast Startup if you haven’t already.

This is where dual-boot problems begin

Why Linux sees your Windows drives as unsafe to modify

Fast Startup may help Windows boot faster, but it quickly becomes a problem when you add another OS to the picture, especially one that treats NTFS partitions differently from Windows.

When Windows shuts down with Fast Startup enabled, it doesn’t actually release the NTFS partitions it was using. The filesystem is left in a suspended state, with cached data still tied to the hibernation image. Windows expects that the next time those partitions are accessed, it’ll be waking up from that exact snapshot—not coming back from a completely different OS that may or may not have moved or modified files in between.

So when you boot into Linux and access those same files or create new ones across the same NTFS partition, you’re writing to a file system that Windows still considers live. It has an old, hibernated view of that partition cached in memory. When you return to Windows, there’s a mismatch between what the OS expects to see and what’s actually present on the drive.

This might not sound like a big problem, but anything that changed while you were using Linux can get flagged as corrupted data, or even get overwritten with the older version without warning.

The damage isn’t always dramatic, and you won’t lose entire data dumps just because you use a shared partition between two OSes for storage. But you can expect some small changes here and there. Sometimes, you just lose a few recently modified or created files; other times, you end up with inconsistencies in a file system that accumulate over time and eventually cause bigger problems like unreadable directories, broken file trees, or a partition that needs a full repair pass to recover.

Linux is trying to save your data

The reason NTFS partitions suddenly become read-only

The Linux kernel is aware of this problem and, to its credit, actually tries to save you. When the NTFS driver detects that a Windows partition was hibernated rather than properly shut down, it mounts the partition as read-only by default. You can still browse your Windows files, you just can’t write to that partition.

But that’s a temporary safety net at best, and it has its limits. It applies only when Linux explicitly detects the hibernation flag, which may or may not happen every time you try to access said partition. To make matters worse, if you forcefully mount a partition using ntfsfix to bypass the read-only restriction, you’re essentially gambling with data integrity.

Linux has been working on improving its NTFS implementation, but it’s different from Microsoft’s approach. The two OSes often disagree on filesystem state in small, subtle ways that can lead to big problems for your files out of nowhere.

Turning it off helps—but not always

Watch out for Windows automatically re-enabling Fast Startup

The only solution to ensure that your Linux files don’t magically disappear, break, or you’re not stuck in read-only mode is to disable Fast Startup in Windows. You can disable Fast Startup and still retain fast boot times, and given the problems this feature can cause, the 30 seconds it takes to disable it is well worth the effort.

The easiest way to do so is to open a PowerShell window with admin privileges and run the following command:

powercfg /h off

This disables hibernation and takes Fast Startup with it. It’s especially helpful considering Windows tends to re-enable Fast Startup after major updates. However, if you’d like to have the option to hibernate your Windows PC or just prefer the graphical interface, disabling Fast Startup isn’t too much of a hassle.

1. Open the Control Panel and head to Hardware and Sound
2. Click Power Options.
3. Click Choose what the power buttons do on the left.
4. Click Change settings that are currently unavailable to unlock the shutdown settings section.
5. Uncheck the Turn on fast startup checkbox and click Save changes.

This works the same way as the PowerShell command above. However, this setting does let you retain the option to hibernate your PC if you want.

One setting can prevent a disaster

The quick toggle that protects your files before something breaks

Fast Startup was mainly intended to serve as a performance boost on slower, mechanical hard drives, which you shouldn’t be using in 2026 in the first place. And if you’ve got a dual-boot PC, having it enabled is just inviting trouble for both your Linux and Windows files.

So take a minute out to check whether Fast Startup is enabled, and if it is, disable it to avoid the hassle. Your SSD won’t let you notice the difference, and your filesystem will thank you for it.