Microsoft Appears to Have Lost the Source Code of an Office Component
bleepingcomputer.com
bleepingcomputer.com
Also, I routinely used the debugger to launch Excel so I could debug my plugins. It faulted (null-pointer) several times during startup. Caught the faults and kept on plugging away. In my opinion, symptomatic of patch upon patch applied to old issues.
We used to blame this on, at Microsoft only new code got you a good review and promotion. So only interns ever worked on existing products .And then they began hiring Juniors in college over the summer for a 90-day summer job to replace internships. After that absolutely nobody would work on old products.
To top it all off, they a couple years ago folded their test groups into their Engineering groups. So now no testing gets done, or if it does the bugs can't stop the schedule. Because the testers are beholden to an Engineering manager instead of an independent organization. So now all Microsoft updates are tested simply by shipping them and sampling the bug reports.
If I had to guess, it's probably because they got really good licensing terms for that version back in the day (e.g. flat fee for unlimited copies), and MathType is smart enough to not offer them a similar deal for a newer version.
http://lomont.org/papers/2007/excel-2007-bug/Excel2007Bug.pd...
Anyway, we failed at computing if we can't edit code a couple of decades old.
More seriously, as the article states, it is the configuration etc. of those build computers. The code is pre-cloud computing (where VMs to build stuff can be archived for pennies), and the build computers are likely gone given how old the component is.