[SOLVED] Will installing VS2015 update 3 VC++ redistributables break other software

Will installing VS2015 update 3 VC++ redistributables break other software

As suggested in this post, If I install the VC++ redistributables for VS2015 update 3 am I likely to break other software running on the same PC built with previous updates to VS2015? Similarly, if I stick with update 2 for my release, is this going to get broken at some point in the future when someone installs the redists for update 3?

Solution

Based on the bug description as reported at New VC Runtime 14.0.24210.0 breaks MFC app built with VS 2015 Update 2 the U3 redistributables will indeed break MFC apps compiled with U2 or earlier, which:

use MFC in a DLL i.e. not statically linked, and
create objects of type CMFCToolBarButton or derived.

From the linked page:

The problem is caused by the new BOOL member m_bIsDragged in class CMFCToolBarButton.
So memory layout differs between Update 2 and 3.
When initializing m_bIsDragged in the constructor, the (stack) memory behind the ToolBarButton is overwritten.

The problem should arise also on all classes which are derived from CMFCToolBarButton:

CMFCColorMenuButton
CMFCCustomizeMenuButton
CMFCDropDownToolbarButton
CMFCOutlookBarPaneButton
CMFCRibbonGalleryMenuButton
CMFCToolBarComboBoxButton
CMFCToolBarDateTimeCtrl
CMFCToolBarEditBoxButton
CMFCToolBarFontComboBox
CMFCToolBarFontSizeComboBox
CMFCToolBarMenuButton
CMFCToolBarMenuButtonsButton
CMFCToolBarSpinEditBoxButton
CMFCToolBarSystemMenuButton

[ EDIT ] For completeness, it should be pointed out that apps that use AppLocal deployment of the MFC/CRT DLLs are not affected, since they do not use the system-wide installed copies thereof.

AppLocal deployment is described under bullet #6 "updated September 11 2015" in "Distributing Software that uses the Universal CRT" at Introducing the Universal CRT.