Increase size of disk container

Hello Wajfromnj,

It seems like you want to add an APFS volume to another container, is that correct? If so, please check out this link, which explains that process and may help: Add, delete, or erase APFS volumes in Disk Utility on Mac

Apple File System (APFS) allocates disk space on demand. When a single APFS container (partition) has multiple volumes, the container’s free space is shared and can be allocated to any of the individual volumes as needed. Each volume uses only part of the overall container, so the available space is the total size of the container, minus the size of all volumes in the container.

On your computer, macOS is installed on a set of volumes known as a volume group. The volume group consists of one volume used for the system files (named Macintosh HD) and another volume used for data (named Macintosh HD - Data).

Add an APFS volume

Each volume you add to an APFS container can have a different APFS format, if needed.

1. In the Disk Utility app  on your Mac, select an existing APFS volume in the sidebar, then click the Add Volume button  in the toolbar.

If Disk Utility isn’t open, click the Launchpad icon  in the Dock, type Disk Utility in the Search field, then click the Disk Utility icon .

2. Enter a name for the new APFS volume.

3. Click the Format pop-up menu, then choose an APFS format.

4. If you want to manually manage APFS volume allocation, click Size Options, enter values in the fields, then click OK.

* Reserve Size: The optional reserve size ensures that the amount of storage remains available for this volume.

* Quota Size: The optional quota size limits how much storage the volume can allocate.

5. Click Add.

6. When the operation is finished, click Done.

Before making changes, we would suggest ensuring you have a current backup of the information on your Mac to ensure it is backed up correctly. You can find more information about that in this link, which may help: Back up your Mac

Take care!

You cannot change the size of the partitions when you have Windows installed. You will need to try to use BootCamp Assistant to uninstall Windows & restore the Windows partition to the macOS partition/container. Then use BootCamp Assistant to reinstall Windows onto a larger partition.

Make sure to have a good backup before attempting to make any changes in case something goes wrong since modifying the partition layouts is a risky & major system change which can possibly lead to data loss if something goes wrong.

If the Windows partition can not be reunited to the macOS partition/container, then you need to start completely from scratch by erasing the whole physical drive followed by reinstalling macOS & restoring from a backup. Plus then trying to reinstall Windows using BootCamp Assistant.