I am writing an app that exports data to excel. It reads existing text files and parses them into columns , which is then made into a CSV file and using an activeX interface, loaded into Excel and ...

Another patch, KB 2553154, is killing some Excel 2010 and 2013 macros, saying the ActiveX control “has stopped working in Excel.” ...

Form Control objects are self-contained within Excel, while ActiveX Control objects use Visual Basic for Applications for formatting and scripting.

It's been quiet for a while, but ActiveX is still around. Upcoming Microsoft Office versions will finally switch off support. At least almost.

The bug is in the ActiveX control that displays Excel spreadsheets within IE, Microsoft said. The timing of the disclosure was particularly awkward for Microsoft.