Boot Camp error: An error occurred while copying the Windows installation files

Question

Level 1

15 points

Boot Camp error: An error occurred while copying the Windows installation files

Continued Conversation from Boot Camp error: An error occurred while copying the Windows installation files

I ran into this issue trying to install the full version of Windows 10 Pro October 2018 using 10.13.1 Mojave. I’m installing on a MacBook Pro 15 (2016).

I verified the system was fully ready to install. However this error occurred over and over. Finally I decided to push through manually and it worked. The problem is under the Windows 10 ISO under the Sources folder, there is a file called install.wim. This single file is over 4GB and can’t be written to a FAT 32 partition that Boot Camp creates. This is a limitation for FAT 32. Here was how I worked around it.

1. Star Boot Camp like normal.

2. Go to the point of failure where you get the error message.

3. Boot Camp will attempt to roll back the parition, but close Boot Camp so those two new partitions are kept. They are named OSXRESERVED and BOOT CAMP.

4. Use Disk Utility to erase the newly created “OSXRESERVED” partition, and with the erase feature, choose the ExFAT Format. (This format will allow you to write larger files than the FAT 32 format)

5. Manually copy all the contents from the Windows 10 ISO to the OSXRESROUCES volume.

6. Restart your Mac and enter into the boot selector (hold option key while restarting).

7. You’ll see an option called “Windows” to boot from. This is the installer.

8. As you go through the Windows installer, make sure to reformat the “Boot Camp” partition using the installer tool (this is step #4 from this help article Install Windows on your Mac with Boot Camp - Apple Support)

9. For the rest of the process follow step #5 from the above article. You’ll be clicking on the link “install Windows support software manually” (here is the direct link here If Windows Support Software isn't installed after you run Boot Camp Assistant - Apple Support)

I hope this helps! I’m staring at my window screen right now so I’m sure this setup worked for me.

Cheers!

MacBook Pro (15-inch, Late 2016), macOS Mojave (10.14.1), null

Posted on Nov 15, 2018 4:12 PM

Reply

Answer 1

Top-ranking reply

evan-13 Author

Level 1

15 points

Nov 15, 2018 4:35 PM in response to evan-13

Continued...

In place of step #9 you can download the Windows Support Drivers by booting back into Boot Camp Assistant and going to the Action drop down menu. Then choose “Download Windows Support Software.” You’ll want to first format a USB Thumb Drive as ExFAT and then save the file directly to this thumb drive.

Reply

Answer 2

MrBoffo

Level 1

4 points

Feb 3, 2019 9:19 AM in response to Loner T

While I'm not the author of the original post, I know what step 5 is. I believe there is a typo there, and that it should read "5. Manually copy all the contents from the Windows 10 ISO to the OSXRESERVED volume." After step 4 you should see a volume named OSXRESERVED on your desktop. Open the Windows 10 ISO. Copy the contents therein into OSXRESERVED. Go on to step 6.

To be honest, I tried this approach, and it didn't quite work. In the end I was able to install bootcamp using the standard installation process simply by using the older version of the Windows 10 ISO from Microsoft. (I think from October 2018?). That ISO does not contain the overly large file that necessitated the ExFAT technique outlined in evan-13's excellent post.

Hopefully Apple will update Boot Camp Assistant to work properly with the newest Microsoft ISO's.

Reply

Answer 3

tperfitt

Level 1

4 points

Dec 11, 2018 3:31 PM in response to evan-13

I created a tool that helps with this issue if you want to use the latest Windows 10 ISO. The "an error occurred while copying the Windows installation files"issue is due to the install.wim file being too large in the ISO, and my tool splits it into smaller parts so it fits on a FAT32 filesystem.

The tool is free and you can read all about/download it here:

https://twocanoes.com/using-larger-windows-10-isos-with-boot-camp-assistant/

Reply

Answer 4

Nov 16, 2018 11:19 AM in response to Loner T

The instal.wim is the problem file been trying different methods all day.

the method mentioned by even-13 works but if you want it easy then install the 1803 version

Reply

Answer 5

Nov 17, 2018 6:34 PM in response to evan-13

So after 8 hours(half a day) I managed to find a solution for my problem. Microsoft just released an installation iso file where the size of some files do not respect FAT32 limitations thus making BootCamp totally unusable.

This manual worked for me just fine.

HOWEVER, I am getting a REALLY REALLY bad sound quality in Windows 10. I have Cirrus Logic 4208 (or what) sound card and the sound is SOOOO bad. I even tried to connect my AirPods and they do not reproduce a good sound either(like the sound transfer is laggy).

Thank you for your manual. Now I have to try to fix my sound issues.
(my MBP is mid 2015 with dGPU)

Reply

Answer 6

tperfitt

Level 1

4 points

Dec 22, 2018 5:54 PM in response to 1slammer

This issue is resolved in the most recent mojave update.

Another option is to use the microsoft media creator. You have to be on Windows to use it (otherwise it just has you download the latest ISO):

https://support.microsoft.com/en-us/help/15088/windows-10-create-installation-media

tim

Reply

Answer 7

Jan 17, 2019 12:22 PM in response to Mroksalmarer513

After updating my Mac OS to 10.14.2 it worked. I neglected someone's post where they mentioned this because I thought my Mac was up-to-date, but lo and behold that minor update does fix the issue I had.

Reply

Answer 8

Loner T

Level 9

59,536 points

Nov 16, 2018 4:06 AM in response to evan-13

The install.wim can be larger than 4GB if there are multiple Windows 'products' in the file.

Reply

Answer 9

Loner T

Level 9

59,536 points

Feb 3, 2019 10:00 AM in response to MrBoffo

W10 1803 (April) has a smaller-than-4GB install.wim.

W10 1809 (October) has a larger-than-4GB install.wim.

Reply

Answer 10

Loner T

Level 9

59,536 points

Jan 7, 2019 5:16 PM in response to D4close

I’m not sure how to do step 5? How do you manually copy the content from the Window ISO to the volume of the OSX?

Mount the ISO in Finder, select all files from the ISO main folder and copy to the USB.

Reply

Answer 11

Dec 26, 2018 7:23 PM in response to evan-13

That link: https://twocanoes.com/using-larger-windows-10-isos-with-boot-camp-assistant/

worked after hours of me trying things on my own. Recommended!

Reply

Answer 12

Nov 17, 2018 7:06 PM in response to Loner T

I thought I might do that but I spent so many hours browsing internet and youtube so I had no patience for it anymore. Tomorrow on Sunday I will try to reinstall it. I will use April version of Windows 10 ISO file. And I will write what happened.

Reply

Answer 13

1slammer

Level 1

4 points

Dec 22, 2018 6:54 PM in response to tperfitt

Ya, I’ve been trying to get a windows machine all day because that would make my life much easier. Went to UPS store and got kicked off their machine 3x in the middle of creating a boot stick, spent 20$ to get nothing accomplished.

About to say f it and go with Linux and make everything work from there. Seems easier at this point.

Reply

Answer 14

Loner T

Level 9

59,536 points

Dec 22, 2018 8:41 PM in response to 1slammer

Total time building new pc...4 hours.

Total time trying to get Windows installed...12 and counting

Total time installing Windows 10 1803 on Sierra on a 2014 Mac (non-APFS macOS) - 1 hour. ;-)

(For everything else, there is a MasterCard/Visa/AmEx/Discover).

Reply

Answer 15

Jan 9, 2019 10:01 AM in response to evan-13

I made it to step 4 before experiencing complications. I tried to manually copy all the contents from the Windows 10 ISO, but when I click on the disk image of the Window ISO I get a message saying "The following disk images couldn't be opened" and the reason given is "Resource busy".

Did you mean to say copy the Windows ISO itself? Because at the moment there are no contents for me to manually copy, because it's an unpacked disk image... I hope you'll reply because after making it to step 4 and this happened I don't know how to proceed.

This ISO is on my desktop btw. I saw in a video that on the new Macs you can't do it without having to use a flash drive.

Reply