The startup disk cannot be partitioned help!

Have you already partitioned your drive using Disk Utility? What is the capacity of your drive? How much free space is there? How is the drive formatted and what is the partition schema?

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I have the exact same problem and the exact same computer as OP.........partition failure error message every single time I've tried using Bootcamp Assistant. I believe it is due to not having enough free disk space. I tried deleting anything non-essential and freed up about 10GB however that didn't help.

I have not already partitioned the drive. 121.xx GB ss drive with 64.79GB free. Partition schema is N/A and Format is APFS Volume (?).

If anyone can assist, please do..... Thanks so much in advance!

Hi Grant. I'm using the version of Bootcamp in 10.13.3 if that helps. Not sure what older tools may be coming into play here, if any. Is APFS formatting of my disk1 preventing Bootcamp from successfully working, and is there some work around I should do?

OK I took a look as you've noted above. GUID Partition map APPLE SSD 128G media if that is what you are referring to? I'm not sure, and certainly not an expert here. Bootcamp keeps failing to partition, and thats all have to go on.

in the default Volume-view, all that can be seen is the MacOS Volume. You cannot subdivide that.

You need to start with the device by Hardware-name, which should be the mentioned "Apple SSD 128G Media".

But that is a mighty small drive to be cutting in half. Windows needs on the order of 100GB, MacOS needs a similar amount.

I see. My thought was replace the 128gb ssd with 500gb or even 1TB perhaps, and then partitioning it. Is the issue space available on the ssd? Is it even worth a shot with the 67 GB free? Apple says you only need 55GB free.

I previously ran windows 7 on a macbook air and install and Bootcamp use was very easy. I no longer own that machine and seriously need win 10 on this newer MacBook pro, requiring the purchase of win10 x64, so I'm $120 in on this endeavor.

Again I am using the Bootcamp Assistant to set up Bootcamp here, not just partitioning via Disk Utility and attempting a Windows 10 install.

What is my best recourse here?

When you do that according to the Boot Camp directions, what error messages do you get?

If it is literally "the startup disk cannot be partitioned" that is the problem.

Just as you cannot saw off the branch you are sitting on, you cannot modify the drive that is running MacOS.

Stand somewhere else (like Recovery or Internet Recovery) and the startup disk will no longer be busy, and Disk Utility will try to modify it.

THE ERROR:

Your disk could not be partitioned.

An error occurred while partitioning the disk.

Please run Disk Utility to check and fix the error.

Excellent description! I UNDERSTAND NOW that I'm sitting on the branch and shouldn't saw through it. I need to stand somewhere else......

So boot from Recovery (need to figure that out) and then run Bootcamp Assistant as the drive I'm trying to modify won't be busy?

OK i see the recovery boot procedure, and Disk Utility from there. Manually partitioning the disk seems the order of the day. My question now is after I partition the drive to accept the install of Windows, do I click on the .iso of Win10 I downloaded, and direct it to install on the new partition?

Never tried this before.....I'll be searching for a walk through.

Last but not least could I use one of my extra external enclosed SATA hard drives, format it for windows, install Windows 10 on it, and run it from there rather than partition my 128GB mac disk?

just a thought that occurred to me to ask.........

That would be a great idea. If it were MacOS, that would be really easy to do, and be fully bootable.

Windoze does not Install on any other drive than the internal drive. Once you have it installed, you may be able to move it.

Excuse the ramblings. Here's where I am. Working from Recovery, I attempted to partition the Apple 128GB disk and all the space i could muster from the drive allowed me just 41 GB. I tried and failed twice to add the 41GB partition "Bootcamp" (MSDOS-FAT) to no avail.....look like i physically need more space/larger ss flash disk. 500GB flash drive will be on its way shortly if I'm to complete this quest.

That may be OK.

Disk Utility in High Sierra uses the extremely unhelpful Volume-View by default:

Use the Icon in the upper left to invoke Device View instead:

you will be far more likely to succeed.

E foda!