Disk First Aid Not Finishing or reporting error (report attached) on system disk / main disk:
This is the report of today, this has happened many times, with several results, but as of today the disk size also seemed incorrect (I thought I had more space left):
Report:
Verifying file system.
Volume could not be unmounted.
Using live mode.
Performing fsck_apfs -n -l -x /dev/rdisk1s1
Checking volume.
Checking the container superblock.
Checking the EFI jumpstart record.
Checking the space manager.
Checking the object map.
Checking the APFS volume superblock.
Checking the object map.
Checking the fsroot tree.
Checking the snapshot metadata tree.
error: snap_metadata_val object (oid 0x60b4c5): invalid extentref_tree_oid (0x0)
Snapshot metadata tree is invalid.
The volume /dev/rdisk1s1 could not be verified completely.
File system check exit code is 0.
Restoring the original state found as mounted.
Completed
MacBook Pro 13″, macOS 10.13