Boot Camp chosen partition size ignored by Boot Camp Assistant

• Disconnect the external disk
• Run BCA and click on Continue -> Remove/Restore
• Run SMC and NVRAM Reset
• Run Disk Utility and choose a size and test if you can create a FAT partition (not an APFS Volume) of the size you want and it is the correct after the partitioning is finished.
• Remove this partition using DU
• Run BCA and try the same and check the size

There are two patches...

• Download macOS Mojave 10.14.5 Boot Camp Update
• Download macOS Mojave 10.14.6 Combo Update

Can you check if either one has been applied to your system? Look at About This Mac -> System Report -> Software -> Installations.

Since you already have a backup, I suggest, installing a clean copy and testing BCA first, before you restore your backup. If it works properly, do not restore macOS, but just your user account and files and settings.

Since you are already on Mojave, try to Download macOS Mojave 10.14.6 Combo Update . See What's new in the updates for macOS Mojave - Apple Support for reference.

Mojave should not change the size of your Bootcamp/Windows partition. Can you check the Console for any error messages?

Can you check if the macOS and BCA version are the same? If they are, can you try to use BCA and see if the partitions are correctly sized?

What is the exact version of macOS? You can run the following command in the Terminal.

sw_vers
ProductName:	Mac OS X
ProductVersion:	10.14.6
BuildVersion:	18G4032

Can you also post the BCA version?

The significant difference is an APFS Fusion vs a single-drive APFS container. Do you have a second Mac running Mojave?

It can also be a bug related to APFS Fusion. You can re-install macOS (the same version you currently have) on the iMac and test.

There is a much simpler method. Boot using Command+R and choose Reinstall macOS. Verify that it offers the same macOS version as your internal disk. This should leave all your non-OS files intact. It would be good to first back up the current state, before you do this.

See How to reinstall macOS from macOS Recovery - Apple Support for reference.

hey Loner T!!! I been reading all a problem you solved a couple years ago, I have a huge problem now and I need to fix it, it’s super urgent and I’ve been sitting here for 2 days, is there anyway I can link with you on WhatsApp or something ? I’m a noob, really need help! 🙏🏻

Needyourhelp23 wrote:

hey Loner T!!! I been reading all a problem you solved a couple years ago, I have a huge problem now and I need to fix it

Can you start a new discussion, and we can try to address your issue(s)?