Hello, The Optimize-FFU option in DISM indeed compresses the FFU image, but it does not necessarily expand the Windows partition to occupy the entire disk space. This is likely the reason why the Windows partition size is reduced and the rest of the drive space is left unallocated. If you want the Windows partition to take up the entire disk space, you will need to manually extend the partition after deploying the image. You can use DiskPart for this. Here’s how you can do it in your MDT Task Sequence: Add a new “Run Command Line” task after the “Apply Image” task in your Task Sequence. In the command line box, type: cmd /c "echo select volume c > diskpart.txt && echo extend >> diskpart.txt && diskpart /s diskpart.txt" This command will create a new DiskPart script that selects the C: volume and extends it to occupy the remaining disk space. Then it runs the DiskPart script. This will ensure that the Windows partition is extended to the maximum size possible after the FFU image is applied. Remember to test this on a non-production environment first to make sure it works as expected. Best Regards, Hania Lian
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