Yes through the documented free-space path in a narrow layout; no as a general promise to preserve an arbitrary existing system.
Omarchy 4.0.1 officially supports a free-space ISO install alongside Windows or another operating system, with LUKS on the new partition by default. That is a parallel installation, not an in-place migration. The full-disk path wipes the selected drive. Existing-Arch overlays, manually prepared ESP layouts, cross-disk free space, and Intel-Mac dual boot do not have the same evidence: current reports show mixed or conflicting behavior, so preserve a tested backup and treat those layouts as experiments rather than extensions of the documented happy path.
The v4.0.1 getting-started guide says this path takes over the entire selected drive and explicitly tells the reader to back up first. Encryption is enabled by default; that does not make the wipe recoverable.
What this means: Use only when the selected drive can be erased. Verify the backup from another machine before booting the installer, and identify the target drive by model and capacity rather than position alone.
The v4.0.1 manual supports installing into unallocated free space alongside Windows or another OS. The new partition remains encrypted by default. Windows BitLocker must be disabled, and the manual directs the user to run limine-scan after installation to add the other OS to Limine.
What this means: This is the narrow preservation path to prefer: make unallocated space using the existing OS, choose Free space install, confirm the disk layout, and keep a recoverable backup. It preserves the other OS; it does not import its applications or data into Omarchy.
Do not generalize the free-space instructions to every custom layout. One open report says quick install did not offer a pre-created EFI partition. Another exact two-NVMe Omarchy 4.0.0 report reached the final ESP mount and failed when Windows and target free space were on different disks.
What this means: Treat cross-disk and hand-partitioned installs as unresolved. Record the full lsblk partition topology and have independent recovery media before attempting them; the documented same-disk flow is not proof for these layouts.
We found no v4.0.1 documentation promising an in-place conversion that preserves an established Arch filesystem, mount layout, bootloader, and user configuration. The linked discussion contains mixed manual attempts and no retained clean round trip, so the install script should not be treated as a migration contract.
What this means: Prefer a fresh Omarchy target plus a separately verified data and configuration migration. If experimenting in place, use a disposable clone or restorable image—not the only copy of the workstation.
The v4.0.1 Mac manual still says Omarchy must be the only installed OS and will wipe macOS. A separate discussion reports a successful free-space install on one MacBookPro16,2, with a manual EFI fallback copy needed for the Option-key picker. That exact report does not override the official limitation or transfer to a MacBook8,1.
What this means: Do not use the community recipe on an irreplaceable Mac without a full recovery path. Treat model identity, T2 status, APFS layout, installer-created ESP, and Option-key boot behavior as separate checks.
The supported path is version-pinned to the v4.0.1 manual. Four current community and issue contexts establish real questions and failure boundaries, not universal failure rates. No destructive installation was performed for this answer.
Supplies the repeated existing-Arch preservation question and mixed manual outcomes.
Supplies the Intel-Mac dual-boot question, corrected model identities, and one exact provisional success report.
Preserves the current official only-OS limitation for Intel Mac installation.
Defines the supported v4.0.1 free-space, BitLocker, encryption, and Limine flow.
Defines the destructive full-disk boundary and the high-level free-space alternative.
Supplies the exact cross-disk ESP mount failure and its hardware layout.
Supplies the open pre-created-ESP detection report.