Unable to join partition back into one after uninstalling windows 10

Nov 19, 2017
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Hello there.

I think i have made a mess of my hard drive. I installed windows 10 on my mac, but because it had so many driver issues, I deleted it on the disk utility.

now I am trying to join the partition into one disk. 100 gb seems to be missing from my drive. my drive consists of 500gb but it says the mac drive is 399gb. but in the pie chart it doesn't look like 100gb its actually 185gb.

i just want the disks to be merge but everytime i try to merge or do anything with the disk it comes up with operation failed. the pictures are below.

any help would be really appreciated. thanks so much.




Cory Cooper

May 19, 2004
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Hello and welcome.

-Which model Mac?
-What version of OS X?
-How did you install Windows 10 - using Boot Camp, or manually?
-Do you have a Time Machine or other backup of your data?

If you used Boot Camp to partition the drive and install Windows 10, then you should have used Boot Camp Assistant to delete the Windows install and partition. Using Disk Utility to delete a Boot Camp partition will cause issues and you'll probably have to totally erase/partition your drive and reinstall. You will lose your data by doing this.


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