CachyOS and Windows 11 dual boot: reserved partitions and the Windows Boot Manager check
ItsOOGWAY · PC guides & recorded tests
CachyOS and Windows 11 dual boot: reserved partitions and the Windows Boot Manager check
How to dual boot CachyOS and Windows 11 on one PC. This recorded walkthrough shows reserving space from an existing Windows volume, creating the CachyOS USB, manual partitioning with Limine, correcting the boot filesystem and reaching a boot menu that includes Windows Boot Manager.
The key checkpoint: Identify the Windows disk layout first and use only reserved unallocated space. The recorded endpoint is a boot menu that includes Windows Boot Manager; preserve recovery access.
Before you start
- Back up important files and retain Windows recovery access before partitioning.
- Identify the actual disk, existing EFI and data partitions; drive letters in footage are examples.
- Review the final installer operations and format flags before applying changes.
Resources from this video
Links, downloads & documentation
Every original URL from the video description is collected here, including recorded releases, setup discussions and related videos. Use the version-specific notes when following a recorded build.
Watch the complete video
Open this video on YouTube ↗. Screenshots below link to their exact recorded moments.
Walkthrough 01
Windows and CachyOS on the same PC
You don't have to replace Windows to give CachyOS its own place on your PC. This boot menu has CachyOS and Windows Boot Manager, and the installed Linux desktop is running from the internal drive. The important part is deciding what the installer is allowed to change. I'll walk through the dual boot choices, the Windows shrink limit I hit, and the Linux boot partition mistake you can avoid. This guide starts with Windows already installed.
Walkthrough 02
Know what will stay and what will change
We're adding Linux into reserved space on the same drive. We aren't reinstalling Windows, and we aren't using Erase disk. Think of the layout in three parts: the existing Windows partitions, the space you're setting aside, and the new Linux boot and root partitions that will go inside that space. Make a backup before resizing a volume.
Walkthrough 03
Prepare Windows before partitioning
Check whether Windows uses BitLocker or device encryption, and keep the recovery key somewhere accessible outside this PC. Follow CachyOS's dual boot prerequisites for encryption, Fast Startup, hibernation and Secure Boot. The screens in this recording don't show all of those checks, so treat them as preparation for your own system rather than assume they're already done because my installer opens. Open Disk Management and identify the physical disk first.
Walkthrough 04
Read the disk layout
Several drive letters can belong to partitions on one disk. In my recording, Windows C, Software D and Games E share the internal SSD, alongside the existing boot and recovery partitions. I'm reducing the Games volume. Don't select C or another drive just because its position looks similar to mine. Right click the selected data volume and open Shrink Volume.
Walkthrough 05
Why Shrink Volume offered so little
Here Windows reports only ten thousand seven hundred and thirteen megabytes of available shrink space. That is much less than the free space shown for the volume. The dialog explains why: some files can't be moved by this shrink operation. Typing a larger number into the box doesn't remove that limit. I used MiniTool Partition Wizard to resize this data volume instead.
Walkthrough 06
Create unallocated space
Check the model and size of the disk, select the intended data partition, and review the new size and unallocated space after it. This step changes the partition layout, so use a verified backup and a tool you're comfortable with. The goal is usable unallocated space, not a new Windows drive letter for Linux. After the operation, the Games partition is about two hundred gibibytes, and the new unallocated area is about a hundred and twenty nine gibibytes.
Windows, its EFI partition and the recovery partition are still in the layout. You can choose a different Linux capacity. What needs to match is the unallocated area you deliberately prepared, not my exact amount or partition number. Download the official CachyOS Desktop ISO and check its checksum.
Walkthrough 07
Prepare and boot the installer USB
Use balenaEtcher to write it to a separate USB, checking the target before flashing. Once the flash and verification finish, restart and choose the UEFI USB entry from the firmware boot menu. Keep the Windows boot entry intact. You're starting the live installer here, not changing the default Windows installation yet. In the live environment, check your connection and start the installer.
Walkthrough 08
Choose the UEFI and bootloader route
Choose your region and keyboard layout. This recording uses UEFI mode with CSM disabled, and Limine as the Linux bootloader. Limine's Linux boot partition in this setup is mounted at slash boot. If you choose a different bootloader, follow its own partition instructions instead of combining its settings with these. Select Manual partitioning, choose the correct internal SSD and locate the free space you prepared.
Walkthrough 09
Use only the reserved Linux space
Don't create a new partition table on a disk whose Windows installation you want to keep. Don't format the small Windows Boot Manager partition. For this route, we'll create a separate Linux boot partition and a Linux root partition within the reserved area. Create the Linux boot partition with four thousand and ninety six mebibytes, FAT thirty two, and slash boot as its mount point.
Walkthrough 10
Create the Linux boot partition
Enable its boot flag. This is the new Linux partition, not the two hundred mebibyte Windows EFI partition at the beginning of my drive. Both can appear in the final layout, and the Windows one should remain outside the Linux formatting operations. Use the remaining reserved space for the root partition.
Walkthrough 11
Create the Linux root partition
In this recording, its filesystem is B tree F S, and the mount point is a single slash. The label is just a name to help identify it. The mount point tells the installer how to use it. Check that the root and boot assignments are on the two Linux partitions you intended to create. If the installer says the boot directory uses B tree F S but requires FAT thirty two, go back and correct slash boot.
Walkthrough 12
Fix the /boot filesystem conflict
That exact warning appears in my recording. The root partition can stay B tree F S; the Linux boot partition in this Limine layout must use FAT thirty two. Don't try to solve this warning by formatting the existing Windows EFI partition. Choose the desktop and software groups you need, then enter your Linux account details.
Walkthrough 13
Desktop and account choices
I'm using Plasma here. These choices don't turn the Windows partitions into Linux partitions. The decisive check is still the storage summary: which disk is targeted, which partitions will be formatted, and which existing partitions remain unchanged. Read the summary before confirming Install.
Walkthrough 14
Audit the installation summary
The new Linux boot area is FAT thirty two at slash boot, and the root area is B T R F S at slash. The existing Windows EFI, recovery and NTFS partitions remain in the before and after layout. During a retry, my summary also deletes two partitions created by the failed Linux attempt. Those are my Linux scratch partitions, not numbers for you to copy on another disk. I did get an Installation Failed message during the first run.
Walkthrough 15
What happened when installation failed
The detail was create pacman keyring, with exit code one. I closed the installer, repeated the setup and retried; there were no off camera commands. The next run completed. That result is separate from fixing the boot filesystem. Don't treat every installer error as evidence that the Windows partitions need to be removed. If that failure repeats, keep the error details and installation log. The official guide recommends restarting into the live ISO after a failed attempt before trying again.
Recheck your selected Linux partitions and connection as you go through setup. The recording shows a successful retry on this PC; it doesn't establish one universal cause for every keyring error. Let the successful installation finish.
Walkthrough 16
Install and choose the internal boot entry
The package and configuration stages can take time, so this part is accelerated. When the finished screen appears, restart and select the internal Limine entry. The firmware menu still includes Windows Boot Manager. Selecting the USB again would take you back into the live environment instead of the installation you've just created. Limine now shows the CachyOS kernels, with Windows Boot Manager under Other systems and bootloaders.
Walkthrough 17
Check the dual-boot menu
The normal CachyOS entry reaches the Linux login screen in this recording. The L T S kernel is another Linux kernel entry, not a separate Windows installation. Use the menu labels to choose the system you actually want to start. On your own machine, also select Windows Boot Manager and check that Windows reaches its desktop.
Walkthrough 18
Verify Windows and keep recovery access
That's the final dual boot test. If you need to choose an operating system independently of Limine, the firmware boot menu gives you another way to select its existing loader. Keep the installer USB and backups until you've checked both paths. Changing boot order and deleting a Windows partition are very different actions. If Windows doesn't appear in Limine, start with the official boot manager instructions linked in the resources section.
Walkthrough 19
If Windows is missing from Limine
CachyOS documents limine scan for discovering boot entries. That's a troubleshooting option, not a command I needed to run in this recording. The Windows entry here is already present. Confirm the existing EFI files and configuration before making changes, and leave the Windows data partitions intact. From here you can use the installed Plasma desktop, add Linux applications and return to Windows when you need it.
Walkthrough 20
Use Linux without abandoning Windows
Keep the system updated and make backups before later partition changes. The useful result is having a deliberate Linux area and a clear way to choose your operating system, rather than guessing which part of the drive the installer should overwrite. The decisions to remember are simple: prepare unallocated space, protect the existing Windows partitions, give Linux its correct boot and root filesystems, and inspect the final changes before installation.
Walkthrough 21
Community and next steps
If you want the fuller desktop and application walkthrough, watch the complete CachyOS installation guide too. Join our Discord for Linux setup help and build testing, and bring the exact error and disk layout when you ask. That makes the next person's setup easier to follow.
If your result differs
| Situation | Next useful check |
|---|---|
| The boot filesystem is rejected | Compare the exact Limine filesystem requirement in the recorded correction and current official installation guide. |
| Windows space or existing partitions look different | Stop before applying changes and identify your own disk layout. Do not copy the recording’s sizes or format unrelated partitions. |
| The installer needs another attempt | Read the recorded retry and retain the intended layout. Recheck the final operations before starting again. |
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