• Size of Win 10 Pro updates from Windows Update VS MS Software Catalog

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    Windows 10 Pro x64 22H2 Build 19045.2965, with 2023-05 Cumulative updates.

    I normally use WUMgr to manage my Windows updates sometime after the AskWoody go-ahead, but recently the availability of recent updates has been delayed, sometimes a few days after the next month’s Patch Tuesday.  Up to a couple months ago, I think the WU Pause Updates may have caused this, but I have since disabled the Pause within WU.  MUMgr is currently in that state, no pending updates (expect to see 2023-06), so today I elected to fall back on the Microsoft Software Catalog to acquire the June Updates.

    My past experience with WUMgr has shown the monthly cumulative update size to be about 104 GB month after month, and I often wondered why it was so consistently so.  One would think that the download size would vary from month to month depending on the complexity of the particular patches.  Today I downloaded the KB5027215 Windows Cumulative Update for June from the MS Software Catalog, and was surprised to see its size was only 744 MB, less than 1% the size of the typical WUMgr/WU download.

    Am I missing something here, like understanding what cumulative means?  Compressed vs not compressed? Is the MS Software Catalog only a delta/incremental update that must be only applied to the most recent monthly update?

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    • #2572963

      I only use WUMgr – on several machines – and it always has the latest updates.
      See our WUMgr How To under the Knowledge Base topic.

      WUMgr does not provide accurate download sizes. This is a known issue.

      cheers, Paul

      2 users thanked author for this post.
      • #2573152

        Thank you, Paul T.  I failed to find this problem under the AskWoody Knowledge Base, but did verify your response from the software author’s WUMgr Issues list on GitHub.

        From Issue #59,  https://github.com/DavidXanatos/wumgr/issues/59

        “The problem is the Windows Update API returns a update size based on ‘maximum size’ and how MSFT calculated this is unknown. If you were to use something like PSWindowsUpdate Powershell Module for comparison you’d see the same size.

        If you actually download the update via the API or tools that use it, it will only download the 839MB it actually needs.

        So sadly its not something that can probably be fixed in this tool as its an issue or limitation of the upstream data”

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