Due to a bug in Windows 11 update KB5124010, playing a sound notification upon receiving an email can cause OE Classic to close unexpectedly.

Temporary Solution

You can immediately resolve this crash by turning off the sound notification:

• Open the main menu in OE Classic and go to Options » General.
• Set sound notification to "No Sound".

Microsoft's Official Statement on This Issue

Microsoft has acknowledged this bug under the Known Issues section for KB5124010:

Known issue: Applications that require AC-3 audio decoding might close unexpectedly.

Symptoms: After installing this update, some applications using AC-3 (Dolby Digital) audio decoding may fail to launch or close unexpectedly when specific audio features are played. This issue primarily affects applications relying on Windows' built-in audio decoding. Most modern applications are unaffected.

Resolution: Microsoft is working on a fix for an upcoming Windows update and will provide more information as it becomes available.

While it is disappointing that an update was released with known stability issues, disabling the notification sound in OE Classic will keep the application running smoothly until Microsoft issues an official fix.