Windows 11 includes a feature called “Fast Startup.” When you shut down your PC, this feature does not actually turn the computer completely off. Instead, it logs you out and then hibernates the core operating system kernel to your hard drive. When you turn the PC back on, it quickly resumes the kernel, making your boot times significantly faster.
However, if you are dual-booting Windows 11 alongside Ubuntu Linux, this feature is disastrous. Because Windows never truly shuts down the hard drive, Linux is locked out of accessing the Windows partition. You will likely encounter “Disk is locked” errors, or find that you cannot mount your Windows drives while using Linux. To fix dual-boot compatibility, you must force Windows to perform a true, complete shutdown.
How to Disable Fast Startup
You cannot find this setting in the modern Windows 11 Settings app; it is buried deep within the legacy Control Panel.
- Click the Start button, type Control Panel, and press Enter to launch it.
- If your view is set to Category, change the “View by” option in the top right to Large icons or Small icons.
- Click on Power Options.
- Look at the left-hand navigation sidebar and click the link labelled Choose what the power buttons do.
- You will notice the “Shutdown settings” at the bottom of the page are greyed out and cannot be clicked.
- Click the small shield icon link at the top of the window labelled Change settings that are currently unavailable. (Provide administrator permission if prompted).
- The checkboxes at the bottom of the window will now be clickable.
- Uncheck the box labelled Turn on fast startup (recommended).
- Click the Save changes button at the absolute bottom of the window.
The next time you shut down Windows 11, it will completely power off the hardware and release all locks on your hard drives, allowing your Linux partition to safely mount and access your files.