@ronnie-wong Hi Ronnie
Yes this is the Macintosh HD and it is the only disk I have. The disk does work fine but when I check it with first aid it gives the following error below. Yes I am upgrading from the disk that is currently working on Sierra It is working fine in Sierra (10.12.6) but when I try to upgrade to high sierra it says it can not upgrade because first aid found an error. I am running iMac late 2014.
Load and verify Logical Volumes B-Trees
Logical Volume Group contains 1 Logical Volume
Load and verify 4F473964-4F4C-43D3-9C34-10A52B766CB2
Load and verify BECB30F2-105A-4C6F-8CFA-D9A74E1371FE
Unable to bootstrap transaction group 4899081: malformed B-Tree
No valid commit checkpoint found
The volume A3B8AA0F-D611-4010-A5D6-65BA9F78A8C0 was found corrupt and needs to be repaired
Storage system check exit code is 1.
I have an iMac with 3 TB Fusion drive, recently I tried to use first aid in the disk utility and it said it could not repair the disk and suggested trying recovery mode. I booted to recovery mode and ran first aid but it said also it could not fix the disk. What are my options is there a good third party utility that can fix the error as I need to upgrade to High Sierra. Currently I am using Sierra and the computer boots and works fine.