Users first spotted this daft behaviour in November 2024, and despite the lag, the Windows behemoth has now said, "Yep, it’s happening on both Windows 10 and 11."

There's no official fix yet. All Vole had to offer was that "the Outlook Team is investigating this issue," which is not exactly comforting.

The problem’s visible if you fancy opening Task Manager and watching CPU usage spike as Outlook does its worst.

Vole did suggest a workaround: jump to the Semi-Annual Channel update, where the issue hasn’t been seen. But doing that means fiddling with the registry using admin powers — something the average enterprise IT team will avoid.

In a delicious twist of irony, Microsoft is still nudging—if not pushing—users toward the New Outlook despite it still lacking several key features.

The classic client has no precise shutdown date, but Redmond's desperation is starting to whiff. As one suspicious observer might mutter, forcing bugs into the old system to drive adoption of the new one sounds like classic Microsoft chicanery.