Ask HN:What's the oldest unresolved, and significant software bug you know of?

If you open an Excel file on different platforms (Windows vs. Mac), date/time values will be four years off if the value was entered on the other platform.

The Windows Blue Screen of Death. I don't think Microsoft will ever fix it.

Selects via index occasionally does not find data when using serializable transaction isolation on Oracle, since about 25 years (see https://stackoverflow.com/questions/11826368/oracle-select-i... )