SCCM UUP Updates and disk space

Question

Hi Everyone,

I understand how UUP works and it's working fine here, however one thing is not clear is how the used disk space is seen by the OS.

For example:

• 100GB volume
• Used space is 90GB (already with a few months of Win11UUP updates downloaded)
• Free space 10GB
• Next month Win11 UUP update comes in and the OS sees it as 8GB so used space is 98GB and free space is 2GB but due to hard links the total space used is much less that 88GB.
• Monitoring tool also sees as Used:98GB/Free:2GB

So the question is:

If the next month Win11 UUP update comes in as 9GB will the OS allow it to be downloaded and written to the disk or will it fail as the OS only sees 2GB free?

I hope it does otherwise I need to keep giving disk space to the volume when it's not actually needed.

Thanks, M

Answer 1

The OS will likely block the download if it sees only 2GB of free space, even though hard links reduce actual disk usage. This is because the OS checks available disk space based on what it perceives, not the real space savings from hard links. To avoid issues, it's best to increase the volume size or clean up older UUP files regularly.