IT Home, October 15: Tech media BornCity posted a blog yesterday (October 14) reporting that Microsoft's October cumulative update KB5127648 has fixed crashes in certain applications caused by AC-3 audio decoding on Windows 11 versions 24H2, 25H2, and 26H2.
IT Home reported on October 4 that Microsoft acknowledged a bug in the optional update KB5124010 scheduled for September 2026, which causes certain applications and games relying on the built-in AC-3 (Dolby Digital) audio decoder to crash.
Based on user feedback, some users experience crashes in the system audio decoding component msmpeg2ac3dec.dll after playing multiple MP3 files simultaneously. Certain older games, media players, or productivity tools that invoke the system's built-in Dolby decoder may cause applications to crash immediately upon launch, or experience unexpected crashes during audio playback or volume adjustments.
Due to the previous lack of an official temporary workaround, affected users had to resort to uninstalling patches as an emergency measure. In the October cumulative update, Microsoft resolved this code path conflict through patch KB5127648. Affected Windows 11 users can now restore normal audio decoding functionality by going to "System Settings > Windows Update," checking for and installing the latest cumulative update, and then restarting their computer.