Windows Client #

Status: Draft. Phase: 4. Common client requirements are on the Clients page.

Versions and filesystems #

WIN-1 (Phase 4, proposed): Windows 11. Windows 10 reached end of support in October 2025.
WIN-2 (Phase 4): Roots on NTFS. ReFS, FAT32, and exFAT are not supported for roots.

WIN-3 (Phase 4, proposed): The agent runs per user, started at sign-in, not as a Windows Service. A service runs as a different account, which complicates access to the user’s files and the user’s key store.

WIN-4 (Phase 4): ReadDirectoryChangesW for live changes, plus periodic rescans. The NTFS change journal (USN) is not used, because it needs administrator rights.

WIN-5 (Phase 4): Long paths (over 260 characters) are handled whether or not the system’s long-path setting is enabled.
WIN-6 (Phase 4): Locked files. Office and other applications hold files open with exclusive locks. The client reads with shared access, retries files it cannot read, and delays applying an incoming change to a locked file. It never fails the whole sync because of one locked file.
WIN-7 (Phase 4): Incoming changes are written to a temporary file and swapped into place atomically, so applications never see a half-written file.
WIN-8 (Phase 4): Names follow the Metadata Matrix name policy: reserved names, forbidden characters, trailing dots and spaces, and case-only collisions.
WIN-9 (Phase 4, proposed): Tolerates antivirus scanning (Microsoft Defender) briefly locking newly written files.

WIN-10 (Phase 4): Windows 11 often redirects Documents, Desktop, and Pictures into OneDrive (“Known Folder Move”). The client detects a root inside a OneDrive-managed folder and warns (ROOT-8).

WIN-11 (Phase 4, proposed): The device private key is held by the TPM (through the Windows platform crypto provider) where available, or else protected with DPAPI.

WIN-12 (Phase 4, proposed): A per-user installer that does not need administrator rights.
WIN-13 (Phase 4): A notification-area (tray) icon and Windows toast notifications (UI-1).

Code signing: unsigned binaries trigger SmartScreen warnings. Is a code-signing certificate worth buying for a personal tool, or are the warnings acceptable?