Mojave - Problems installing Windows 10 with Boot Camp

[Mason]

I need a working Win10 installation but can't get Boot Camp to install it on my iMac (Retina 5K, 27-inch, Late 2015).

I have downloaded the 64 bit ISO - Win10_1803_English_x64 which is under 5GB so should work.

I opted for an 80GB partition and Boot Camp creates this then downloads the Windows Support Files and copies the files across from the ISO. It then fails saying that the Windows Support software could not be saved to the selected drive.

I've tried several supposed fixes thrown up by a Google search but nothing works. I can remove the Bootcamp partitions and revert to OSX only.

I then decided to try one last thing. When I start bootcamp it suggests a windows partition size of 56GB which I then increase to 80GB, on my last attempt I decided to leave it at the suggested size of 56GB bootcamp fails in exactly the same way. When I opened the Disk Utility app to remove the Bootcamp partitions I noticed that t had formatted it to 80GB even though I'd left it set to 56GB so there's definitely something odd going on.

Any help sorting this out would be greatly appreciated.

Thanks

[chscag]

Unless I'm not understanding what you posted, it sounds like you're trying to install the support files before installing the Windows 10. How can you install the support files (Boot Camp drivers for Windows) before Windows 10 has been installed?

[Mason]

Unless I'm not understanding what you posted, it sounds like you're trying to install the support files before installing the Windows 10. How can you install the support files (Boot Camp drivers for Windows) before Windows 10 has been installed?

Yes, you're not understanding what's happening.

I'm not installing anything the entire process is down to Bootcamp. The first thing Bootcamp does is download the Windows support files, these are temporarily stored on the mac. It then partitions the drive creating a bootcamp Windows partition and an install partition, I believe on earlier versions of OS X this was done via a USB drive rather than an install partition.

Once the partitions are created Bootcamp then copies the windows files it needs for installation and it also copies the downloaded windows support files to the install partition and this is the point where it fails with the message Windows Support software could not be saved to the selected drive. At this point bootcamp is still putting the files it needs on the new partition it hasn't even started to install windows let alone the Bootcamp drivers.

[dtravis7]

That is a strange one. Does it allow you to specify where to save the Windows Support Files? I have not done Bootcamp in a few years. Way back I was able to save the Support files where I wanted to. Guess things have changed.

I will search around and see what I can find.

[dtravis7]

Cause

Apple allows Windows Installation, by first copying the entire ISO into a temporary storage area. Most of the time it works, because there is enough space available.

When we use a larger ISO, like the 32-bit + 64-bit Windows ISO, it requires about 6.5 GB just for the storage, let alone uncompressed files usage. Apple tried to download Windows support software onto that partition. This is where the issue happens. The package requires at least 1 GB, and it would not get it because of the ISO.

Solution

Use the 64-bit ISO (3.5GB) instead of the 32-bit + 64-bit Windows ISO for a x64 MacBook (all current generation ones)
Use the 32-bit ISO (3.5GB) instead of the 32-bit + 64-bit Windows ISO for a x86 MacBook (2011 etc.)

I sure hope this helps.

[chscag]

Thanks Dennis. I haven't installed Windows for some time (not since Windows 7 on an older iMac that I had) and forgot that Boot Camp now does things differently. At one time, the support files were installed after the Windows installation had completed.

[dtravis7]

Thanks Dennis. I haven't installed Windows for some time (not since Windows 7 on an older iMac that I had) and forgot that Boot Camp now does things differently. At one time, the support files were installed after the Windows installation had completed.

Same here. I found that in a search and it solved the persons issues. I used to have it copy the support files to an external USB drive.

In the OPs first post he said he had just the 64 bit installer and it was less than 5GB. I am sure what I posted is his issue but it sounds like he has the smaller ISO.

[Mason]

Cause

Apple allows Windows Installation, by first copying the entire ISO into a temporary storage area. Most of the time it works, because there is enough space available.

When we use a larger ISO, like the 32-bit + 64-bit Windows ISO, it requires about 6.5 GB just for the storage, let alone uncompressed files usage. Apple tried to download Windows support software onto that partition. This is where the issue happens. The package requires at least 1 GB, and it would not get it because of the ISO.

Solution

Use the 64-bit ISO (3.5GB) instead of the 32-bit + 64-bit Windows ISO for a x64 MacBook (all current generation ones)
Use the 32-bit ISO (3.5GB) instead of the 32-bit + 64-bit Windows ISO for a x86 MacBook (2011 etc.)

Hi Dennis,

Now that makes perfect sense.

I know the October release of Windows 10 doesn't work because there are size issues but I'm using the April release of the ISO and according to everything I read this one should work, but it doesn't and the ISO slightly less than 5GB in total.

It may be that the error message is misleading. It's telling me the support files could not be saved to the selected drive, perhaps it should say because the disk is full.

I need to find the smaller 3.5GB ISO file and see what happens. Unfortunately a quick look on the Microsoft site only offers the October release which is massive and the slightly smaller April release at just under 5GB.

Does anyone have a link to the smaller ISO?

[dtravis7]

Let me see if I can find anything. will post back with a URL if I do.

[dtravis7]

They talk about the Win 10 Creators 64 bit ISO here and say it's 3.5GB. Read all the posts.

https://answers.microsoft.com/en-us/...d-3d38cc7c7b32

[Mason]

Thanks Dennis. I haven't installed Windows for some time (not since Windows 7 on an older iMac that I had) and forgot that Boot Camp now does things differently. At one time, the support files were installed after the Windows installation had completed.

Same for me too.

I installed Win7 on my 2010 Macbook Pro and it was a breeze. I only need it because I do volunteer IT support for a group and there are more of them on Windows 10 now than 7 otherwise I wouldn't bother.

[Mason]

They talk about the Win 10 Creators 64 bit ISO here and say it's 3.5GB. Read all the posts.

https://answers.microsoft.com/en-us/...d-3d38cc7c7b32

Thank you Dennis, I'll download the smaller file and let you know how it goes.

[Mason]

The link you posted takes me to the same place I downloaded my ISO from and it only offers either the October release or the April release in either 32 bit or 64 bit and the smallest ISO is 4.7GB

I'm currently searching for the 3.5GB ISO

[dtravis7]

in that URL is a name. They call it Creative something. I was hoping that would help you find what they are talking about. I will search also.

[Mason]

I've also tried by booting to Win7 and instead of the on-line creation tool it downloads a media creation tool. I'm currently downloading the 64 bit ISO but I think it's the same as I already have.

It seems MS defaults to the latest two builds which presumably contain updates and fixes and are therefore bigger. It does not give me the choice to download an older, smaller, ISO that I can load and then run Windows update. The older files are probably there somewhere but I'm struggling to locate them at the moment.

All credit to MS for trying to make it simple and not confuse people with a multitude of options and choices but it's very tedious for people who need something specific for some reason.