[wix-users] Unchanged files break patch uninstall

Sanketh pbsanketh at gmail.com
Wed Jun 21 11:13:05 PDT 2017

Hello All,

We have an issue with patch uninstall, I.e. Unchanged files break patch
uninstall. Any inputs to avoid this?

General Information:

We use WIX 3.10.3 to build both our Base Msi and Patch Msp.

Supports Windows Installer version 301

Patch is build using Purely Wix method as documented.

Root Cause for the issue:

Base Msi contained a file named "Sample.dll" with version as and
language as "neutral".

While building patch, WIX considered there was change to the contents of
Sample.dll but the version is retained as "" and language as

Sample.dll used for Patch creation, even though there was no change to the
contents but somehow we were able to identify there was binary change when
compared with the base and the msp dlls used for creation. Refer below
screenshot from Beyond Compare* ( *https://i.stack.imgur.com/VX3RD.png )

During installation of Base and then patch, as per Windows Installer File
Versioning rules ( https://msdn.microsoft.com/en-
us/library/windows/desktop/aa368599(v=vs.85).aspx ) , the file "Sample.dll"
was not re-installed by patch since the version and language are same.

Hence while removal of patch, windows installer requested the source of the

This is causing uninstallation failures at our customers as the sources of
the msi are not available during uninstall.

Here's a blog entry which said this issue is identified in Windows
installer version 301 ( https://blogs.msdn.microsoft.c
om/heaths/2007/06/28/unchanged-files-break-patch-uninstall/ ).

We had already tried updating the installer version support to 405 in WIX
and still the problem occurs.

Here the patch creation considers the Binary change between the base msi
and patch msi to create the Msp whereas windows installer consider
considers File versioning rules while installing. Is there some changes
that could help avoid such scenarios and how to ensure that only really
changed files are considered for patch creation and installation?

Thanks and Regards,


Best regards

Sanketh P B,
Mob: +91-9740301989

More information about the wix-users mailing list