Bootcamp自由空间不等于实际空间

我试图在我的MBP 2016上使用Bootcamp安装Windows，而我发现可用空间不等于实际可用空间：

我有240 GB可用，但Bootcamp说我只有2GB的可用空间。

这是输出 diskUtil list：

/dev/disk0 (internal):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                         500.3 GB   disk0
   1:                        EFI EFI                     314.6 MB   disk0s1
   2:                 Apple_APFS Container disk1         500.0 GB   disk0s2

/dev/disk1 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +500.0 GB   disk1
                                 Physical Store disk0s2
   1:                APFS Volume MAC                     265.1 GB   disk1s1
   2:                APFS Volume Preboot                 44.9 MB    disk1s2
   3:                APFS Volume Recovery                1.0 GB     disk1s3
   4:                APFS Volume VM                      2.1 GB     disk1s4

和 diskutil apfs list：

APFS Container (1 found)
|
+-- Container disk1 050EA8A3-B6E6-4950-AE74-CF7B63369E42
    ====================================================
    APFS Container Reference:     disk1
    Size (Capacity Ceiling):      499963170816 B (500.0 GB)
    Minimum Size:                 438097276928 B (438.1 GB)
    Capacity In Use By Volumes:   272533753856 B (272.5 GB) (54.5% used)
    Capacity Not Allocated:       227429416960 B (227.4 GB) (45.5% free)
    |
    +-< Physical Store disk0s2 168DEE88-034B-42DF-B32C-0CCC7C4D14B3
    |   -----------------------------------------------------------
    |   APFS Physical Store Disk:   disk0s2
    |   Size:                       499963170816 B (500.0 GB)
    |
    +-> Volume disk1s1 AC76F944-9764-4AF3-87A5-404F8F19C490
    |   ---------------------------------------------------
    |   APFS Volume Disk (Role):   disk1s1 (No specific role)
    |   Name:                      MAC (Case-insensitive)
    |   Mount Point:               /
    |   Capacity Consumed:         269145038848 B (269.1 GB)
    |   FileVault:                 No
    |
    +-> Volume disk1s2 DF3F6FF3-7CF8-4712-BF36-3986E3C2AB27
    |   ---------------------------------------------------
    |   APFS Volume Disk (Role):   disk1s2 (Preboot)
    |   Name:                      Preboot (Case-insensitive)
    |   Mount Point:               Not Mounted
    |   Capacity Consumed:         44933120 B (44.9 MB)
    |   FileVault:                 No
    |
    +-> Volume disk1s3 2210A1EC-15A2-4013-8A93-89AB7CD59897
    |   ---------------------------------------------------
    |   APFS Volume Disk (Role):   disk1s3 (Recovery)
    |   Name:                      Recovery (Case-insensitive)
    |   Mount Point:               Not Mounted
    |   Capacity Consumed:         1035476992 B (1.0 GB)
    |   FileVault:                 No
    |
    +-> Volume disk1s4 FA41CF69-ACF7-4343-9962-66A217CDCE27
        ---------------------------------------------------
        APFS Volume Disk (Role):   disk1s4 (VM)
        Name:                      VM (Case-insensitive)
        Mount Point:               /private/var/vm
        Capacity Consumed:         2147504128 B (2.1 GB)
        FileVault:                 No

好像我有未分配的空间。但是，系统信息告诉我，我有500 GB的全部：