"The startup disk cannot be partitioned or restored to a single partition" error in Boot Camp Assistant

Ok, I actually got BCA to partition using the suggestion here: https://discussions.apple.com/thread/8086777?answerId=32347284022#32347284022

I now have a clean partition running v1709. Given my previous issues with updating and the fact that I didn't have any critical files on my previous partition, I might stick with this, rather than restoring from Winclone and trying to update again.

Also, my idea of using a resize to update to v1709 was from this link

https://answers.microsoft.com/en-us/windows/forum/windows_10-update/feature-upda te-to-windows-10-version-1709-on-mac/e1043f78-2b40-472a-b9ab-353b3cff8711?auth=1

But I realize now that BCA doesn't natively support resizing/updating Windows, right? Following this guide would have just been wiping the existing partition and installing a new one anyway?

Thanks! I have successfully removed my Windows partition and will soon be reinstalling Windows.

I should have mentioned this, but my original goal of resizing in BCA was actually not a larger partition, but to update Windows 10 to v1709. Do you think I would be fine if I restored using Winclone (to v1703) and then did a trivial resize in BCA using the 1709 ISO to update?

Actually, I've encountered a more immediate issue. Both BCA and DU are failing to partition my disk. Trying in BCA has left an image called CCCOMA_X64FRE_EN-US_DV9 that is the same size as the Windows 10 ISO.

/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 179.0 GB disk0s2

3: Microsoft Basic Data BOOTCAMP 321.0 GB disk0s3

/dev/disk1 (synthesized):

#: TYPE NAME SIZE IDENTIFIER

0: APFS Container Scheme - +179.0 GB disk1

Physical Store disk0s2

1: APFS Volume Macintosh HD 147.3 GB disk1s1

2: APFS Volume Preboot 22.3 MB disk1s2

3: APFS Volume Recovery 506.6 MB disk1s3

4: APFS Volume VM

I don't have a backup of the files only, but I do have full disk image backups from Winclone 6. I can make a backup of just the files, though, so I'm fine wiping it.

I'm not sure how else I would update, however. Winclone will push me back to v1703 and trying to update using the update software on Windows was what got me to this point.

I have a 15" 2017 MacBook Pro.

FC? The update just said that it failed, it unfortunately did not give an error message or a reason why. I still had plenty of space left on both partitions.