Bootcamp Error: "Your disk could not be partitioned". Windows 10 installation - REPOST

Here it is:

Resize limits for APFS Physical Store partition disk0s2:

  Current Physical Store partition size on map:   500.0 GB (499963174912 Bytes)

  Minimum (constrained by file/snapshot usage):   499.9 GB (499900616704 Bytes)

  Recommended minimum (if used with macOS):       500.0 GB (499963174912 Bytes)

  Maximum (constrained by partition map space):   500.0 GB (499963174912 Bytes)

Here is the output of "sudo tmutil listlocalsnapshots /":

com.apple.TimeMachine.2019-07-08-150959

com.apple.TimeMachine.2019-07-08-160949

com.apple.TimeMachine.2019-07-08-171341

com.apple.TimeMachine.2019-07-08-181045

com.apple.TimeMachine.2019-07-08-191016

com.apple.TimeMachine.2019-07-08-201047

com.apple.TimeMachine.2019-07-08-211033

com.apple.TimeMachine.2019-07-08-221000

com.apple.TimeMachine.2019-07-09-002207

com.apple.TimeMachine.2019-07-09-105416

com.apple.TimeMachine.2019-07-09-135827

com.apple.TimeMachine.2019-07-09-143027

According to the date, this is the TimeMachine backup from scratch that I performed before creating the minuscule FAT partition. The one that I mentioned at the beginning of this thread, that it took the whole night.

My TimeMachine setup uses an external HDD for backups. From your comment, it seems that TimeMachine is also storing data in the internal SSD.

I have deleted all the snapshots stored locally.

The output of "sudo tmutil listlocalsnapshots /" confirms that there are no snapshots left.

Disk Utility now allows to choose the size of a new FAT partition. I don't do it. Just looking out of curiosity. This is progress.

BC Assistant returns an error: "Your disk could not be partitioned. An error occurred while partitioning the disk. Please run Disk Utility to check and fix the error".

I run Disk Utility to fix the error. This is the ouput after the "First Aid" execution. Please note that the "warning" is no longer there. This is more progress.

Running First Aid on “1_LAPTOP 512GB” (disk1s1)

NOTE: First Aid will temporarily lock the startup volume.

Verifying file system.

Volume could not be unmounted.

Using live mode.

Performing fsck_apfs -n -l -x /dev/rdisk1s1

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 1_LAPTOP 512GB was formatted by newfs_apfs (748.77.8) and last modified by apfs_kext (945.200.129).

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.

Performing deferred repairs.

The volume /dev/rdisk1s1 appears to be OK.

File system check exit code is 0.

Restoring the original state found as mounted.

Operation successful.

I re-run BC Assistant. I get the same error again.

The output of "diskutil list" is:

The output of "diskutil apfs resizeContainer disk0s2 limits" is:

Current Physical Store partition size on map: 500.0 GB (499963174912 Bytes)

Minimum (constrained by file/snapshot usage): 399.4 GB (399369175040 Bytes)

Recommended minimum (if used with macOS): 410.1 GB (410106593280 Bytes)

Maximum (constrained by partition map space): 500.0 GB (499963174912 Bytes)

Please note that the " Minimum (constrained by file/snapshot usage)" has been lowered from 499.9 GB to 399.4 GB. More progress.

However, "sudo tmutil listlocalsnapshots /" returns no local snapshots.

The output of "sudo fsck_apfs -n -l /dev/rdisk1" is:

** 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 1_LAPTOP 512GB was formatted by newfs_apfs (748.77.8) and last modified by apfs_kext (945.200.129).

** 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 (748.77.8) and last modified by apfs_kext (945.200.129).

** 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 (748.77.8) and last modified by apfs_kext (945.200.129).

** 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 (748.77.8) and last modified by apfs_kext (945.200.129).

** Checking the object map.

** Checking the snapshot metadata tree.

** Checking the snapshot metadata.

** Checking the extent ref tree.

** Checking the fsroot tree.

warning: found orphan file extents (id 328, size 85159936)

** Verifying allocated space.

** Performing deferred repairs.

** The volume /dev/rdisk1 appears to be OK.

I see that APFS is a newest, SSD-optimized, format file, while JHFS is an oldest, HDD-optimized.

Therefore, APFS is preferable in my case.

I plan to re-restore tonight:

1. Update to macOS 10.14.5
2. Complete a new TM backup.
3. Check that the TM backup includes all data, non-corrupted.
4. Internet Recovery: Disk Utility: Delete macOS partition.
5. Internet Recovery: Restore from TM backup.

Could you please confirm whether, in step 4 above, I should delete "APPLE SSD AP05..." or "1_LAPTOP 450GB"?

Currently, I only have available one external HDD with 4 partitions.

I have erased one of the partitions with APFS format and installed Mojave 10.14. I haven't upgraded to 10.14.5 yet.

I noticed that now my laptop boots directly from the external drive (I know how/where to change this), but that if I press Cmd+R, the external HDD partition with macOS doesn't show on the list. In other words, I can do normal boot from the new external partition but not "special" boots. I wonder if it is due to have installed in a partition, instead of in the plain/base HDD.

I hope this setup is enough to fix my laptop file format, but, in any case, I have bought a small external SDD that I will receive past-tomorrow and which will give me one "whole" external disk for external booting.

What should be the next step? Should I...?

1. Boot from external HDD with Mojave 10.14.5.
2. Delete/format the internal partition "1_LAPTOP 450GB" with APFS.
3. Install Mojave10.14 in "1_LAPTOP 450GB"
4. Upgrade "1_LAPTOP 450GB" to 10.14.5.

Given that the current file format HFS problem is due to having an internet recovery partition with High Sierra, it would be great if I could delete it (or upgrade it to Mojave), as I don't plan to use it again and I want to prevent the current problem from happening again in the future by mistake.