Bootcamp - can't save Windows support software, not enough space on available disk

Question

So I keep getting the above error at the following step,

1. Downloading windows support software - OK
2. Partitioning disk - OK
3. Copying windows files - OK
4. Saving windows support software - ERROR

I have tons of free space on my SSD (MBP mid-2015) and I'm allocating 140GB for Bootcamp partition.

Below is the output of diskutil list,

roberts-mbp:~ robertdunbar$ diskutil list
/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.3 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                 Apple_APFS Container disk1         500.1 GB   disk0s2

/dev/disk1 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +500.1 GB   disk1
                                 Physical Store disk0s2
   1:                APFS Volume Macintosh HD            65.1 GB    disk1s1
   2:                APFS Volume Preboot                 45.2 MB    disk1s2
   3:                APFS Volume Recovery                522.7 MB   disk1s3
   4:                APFS Volume VM                      1.1 GB     disk1s4

The output of fsck_apfs -s -o -y /dev/rdisk1 is as follows,

roberts-mbp:~ robertdunbar$ sudo fsck_apfs -n -l /dev/rdisk1
Password:
** Checking the container superblock.
** Checking the EFI jumpstart record.
** Checking the space manager.
** Checking the space manager free queue trees.
** Checking the object map.
** Checking volume.
** Checking the APFS volume superblock.
** The volume Macintosh HD was formatted by diskmanagementd (945.250.134) and last modified by apfs_kext (945.250.134).
** Checking the object map.
** Checking the snapshot metadata tree.
** Checking the snapshot metadata.
** Checking the extent ref tree.
** Checking the fsroot tree.
** Checking volume.
** Checking the APFS volume superblock.
** The volume Preboot was formatted by newfs_apfs (748.1.46) and last modified by apfs_kext (945.250.134).
** Checking the object map.
** Checking the snapshot metadata tree.
** Checking the snapshot metadata.
** Checking the extent ref tree.
** Checking the fsroot tree.
** Checking volume.
** Checking the APFS volume superblock.
** The volume Recovery was formatted by newfs_apfs (748.1.46) and last modified by apfs_kext (945.250.134).
** Checking the object map.
** Checking the snapshot metadata tree.
** Checking the snapshot metadata.
** Checking the extent ref tree.
** Checking the fsroot tree.
** Checking volume.
** Checking the APFS volume superblock.
** The volume VM was formatted by newfs_apfs (748.1.46) and last modified by apfs_kext (945.250.134).
** Checking the object map.
** Checking the snapshot metadata tree.
** Checking the snapshot metadata.
** Checking the extent ref tree.
** Checking the fsroot tree.
** Verifying allocated space.
** The volume /dev/rdisk1 appears to be OK.

Help appreciated.