This is normal. Windows sees the VMFS partition type (0xFB or 0xFC) as unknown. Tools like StarWind bypass this.
For most Windows admins: Use StarWind V2V Converter’s hidden VMFS mount feature. It is free, requires no reboot, installs in seconds, and just works with VMFS 6 datastores from ESXi 8.0. mount vmfs 6 windows hot
For power users: 7-Zip’s \\.\PhysicalDrive trick is a lifesaver when you cannot install any software. This is normal
Avoid: Trying to use old VMware DiskMount, Linux WSL with vmfs-fuse (requires reboot for WSL2 kernel updates), or any tool that says "VMFS 5 only". requires no reboot
StarWind offers a free VMFS driver for Windows. It mounts VMFS 3/5/6 volumes as read-only locally.