I understand there are several topics just like this, but I've tried plenty of methods to no avail, and was wondering if I could get help. I deleted Windows off the partition though not out of Bootcamp, which I hear is the main cause of the error, and now I have two partitions and cannot merge them.
I'm own El Capitan if that makes any difference.
iMac
Hi there Nikul.Patel,
If I understand correctly you are trying to merge your old Boot Camp partition into your Mac OS partition but this error is preventing you. Take a look at this article because it mentions the same error message and seems to be specifically for your issue here:
Boot Camp: Partition alert message when using Boot Camp Assistant
CLOS
The simplest and safest method to get your disk corrected is to
1. Backup OSX and all your files - Use Time Machine to back up or restore your Mac - Apple Support .
2. Boot into Internet Recovery (Command+Opt+R) - OS X: About OS X Recovery - Apple Support .
3. Click on Utilties -> Disk Utility and Erase your internal whole disk.
4. Restore OSX and your files - Use Time Machine to back up or restore your Mac - Apple Support .
This requires a separate external disk which can accommodate TM backup - Backup disks you can use with Time Machine - Apple Support .
The startup disk cannot be partitioned or restored to a single partition.
