We help IT Professionals succeed at work.

Differences between full & delta Windows update file

High Priority
Last Modified: 2018-07-02
What are the differences between the full and delta Windows update files?

For example, the Windows update KB428488 has two files available on the update catalog website (see below).

When would I use the full installation file as opposed to the delta installation file?

windows10.0-kb4284880-x64_34d88e02608fa8c7db3dda395434d93ba109169c.msu (1.3 GB)

windows10.0-kb4284880-x64_delta_ddc8a4e151a275c051e35329abe2fdc6cac13eb8.msu (727 MB)
Watch Question

Distinguished Expert 2018
Delta files are for IT Pros that are very diligent aboutut patching and need to load patches onto a management system. They are smaller.

If you don't already have something on place that has done every delta on order then you need the full.  If you have to ask, chances are you also need the full.
DrDave242Principal Support Engineer
Since Windows updates are now released as cumulative updates on a monthly basis, every full update contains all of the previous months' updates as well as the current ones. The delta updates only contain the changes in the current month's update, so they'll always be smaller.

If a particular machine already has the previous month's update installed (which implies, due to the nature of the cumulative updates, that it also has every prior month's updates installed), then it only needs the delta update. A newly-installed machine would require the full update.

More information can be found here.

Explore More ContentExplore courses, solutions, and other research materials related to this topic.