How to fix an 'Invalid Volume free block count' partition failure on MacWhy did I get "operation failed" and "This disk needs to be repaired" when I tried to partition my Mac's hard drive?
Over the weekend, I finally had time to download and install the developer beta of macOS High Sierra. I decided to partition my hard drive so I could keep using my Mac for work without worrying that all my apps and programs would crash under the new software.
I was thwarted right from the start with an "Operation failed" error message while trying to partition my hard drive. Sigh.
After a bit of poking around, I finally came up with a solution that will, hopefully, work for anyone else that comes across this problem.
For reference, the error message for my particular issue was the following:
Invalid volume free block count
(It should be 10069792 instead of 10069785)
The volume Macintosh HD was found corrupt and needs to be repaired.
If you have an error significantly different than the one above, this troubleshooting guide might not solve your problem.
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Source:
How to fix an 'Invalid Volume free block count' partition failure on Mac
