Disk Partition failed -- invalid volume free block count I tried to partition my Disk but it failed with this message:



I have tried First Aid under Recovery and it said the First Aid is completed. However, the partition still failed. What should I do?

My specs:
Macbook pro 2015 Retina model.
8G RAM 256G SSD.
macOS Sierra  

[Edit]

Under Recovery, I can only run First Aid on the disk not on the "Macintosh HD" volume because it is greyed out. Another thing to mention is I installed rEFInd on my Mac as I was planning to install Ubuntu alongside macOS. Is any of this relevant to my problem?
Have you tried running it a second time? Often with "File system check exit code is 8", others have had success repairing a second or third time. 

You may also try booting from the recovery partition and running doing the repair. You can boot from the recovery partition by restarting and holding down the Option key, then select the Recovery partition.

If you don't have a recovery partition, you can do an Iternet Recovery by hold down the Command Option R keys. 

Here is discussion on Apple's Communities forum.