/dev/rdisk1s1: fsck_apfs started at Mon Nov 26 11:38:26 2018
/dev/rdisk1s1: ** Checking the container superblock.
/dev/rdisk1s1: ** Checking the EFI jumpstart record.
/dev/rdisk1s1: ** Checking the space manager.
/dev/rdisk1s1: ** Checking the space manager free queue trees.
/dev/rdisk1s1: ** Checking the object map.
/dev/rdisk1s1: ** Checking volume.
/dev/rdisk1s1: ** Checking the APFS volume superblock.
/dev/rdisk1s1: ** The volume Macintosh HD was formatted by hfs_convert (748.21.6) and last modified by apfs_kext (945.200.129).
/dev/rdisk1s1: ** Checking the object map.
/dev/rdisk1s1: ** Checking the snapshot metadata tree.
/dev/rdisk1s1: ** Checking the snapshot metadata.
/dev/rdisk1s1: ** Checking the extent ref tree.
/dev/rdisk1s1: ** Checking the fsroot tree.
/dev/rdisk1s1: error: btn: invalid btn_btree.bt_key_count (expected 4864041, actual 4864092)
/dev/rdisk1s1:    fsroot tree is invalid.
/dev/rdisk1s1: ** The volume /dev/rdisk1s1 could not be verified completely.
/dev/rdisk1s1: fsck_apfs completed at Mon Nov 26 11:42:46 2018