Microsoft is so keen for users to migrate to the New Outlook email client that it has broken Classic Outlook again. This time, affected users are unable to open or create a message.

An email client unable to open or create emails is sub-optimal. Considering that plenty of users are likely to stick with Classic Outlook until Microsoft [1]wrenches it from their fingers, it's a little embarrassing for Redmond.

[2]According to Microsoft, "the emerging cases for this issue are on virtual desktop infrastructure (VDI)." This means that users running Outlook locally are unlikely to be affected. However, for those who are, the problem lies with the Forms Library and can occur for Outlook on all Microsoft 365 Office Channels.

[3]

Some lucky users might be able to work around the issue by creating a new FORMS2 folder in the %localappdata%\Microsoft path, but others will have to seek alternative means to access their email until a fix is deployed. "This issue has been escalated for investigation," Microsoft stated, without providing an estimate for when it would be resolved.

[4]Microsoft admits it's not you, Classic Outlook can be a real CPU, power hog sometimes

[5]Microsoft's many Outlooks are confusing users – including its own employees

[6]Oops, they did it again: Microsoft breaks Outlook with another dubious update

[7]Eight days later, Microsoft Outlook users still struggle on iOS devices

Classic Outlook hasn't been having the best time lately. There are also [8]issues with flickering folders in a shared mailbox when moving items around. Still, Microsoft appears to have doubled down with the latest problem – the odd flicker is nothing compared to a full-on crash when trying to use the email client to send an email.

For weary enterprise IT administrators, it must feel like different teams within Microsoft are competing to see which can drop the least tested code. The Microsoft 365 team might have sent out an update that caused Classic Outlook to fall over when creating or opening an email, but that is nothing compared to the Windows team, who appear to have bricked several of the company's own devices with a [9]"security and quality" update .

[10]

In April, Microsoft CEO Satya Nadella [11]claimed that approximately 30 percent of code in some of Microsoft's repositories was now written by generative AI. Users faced with yet another broken update will be pondering exactly where this AI-generated code can be found in the company's codebase. ®

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[1] https://www.theregister.com/2025/03/25/too_many_outlooks/

[2] https://support.microsoft.com/en-gb/office/classic-outlook-crashes-opening-or-starting-a-new-email-1b413573-7dfc-4147-9c53-c2f1183b89b8

[3] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offprem/saas&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2aFGRGd2VQXiXubhiu0dQhwAAAkQ&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0

[4] https://www.theregister.com/2025/04/16/classic_outlook_cpu_spike/

[5] https://www.theregister.com/2025/03/25/too_many_outlooks/

[6] https://www.theregister.com/2025/03/20/outlook_outage_again/

[7] https://www.theregister.com/2025/03/11/outlook_ios_problems/

[8] https://support.microsoft.com/en-gb/office/shared-mailbox-folders-flicker-and-move-around-when-trying-to-move-items-to-the-folders-2fa078b0-7d31-4536-a6e2-25a8f19a53ff

[9] https://support.microsoft.com/en-gb/topic/june-10-2025-kb5060533-os-builds-19044-5965-and-19045-5965-eeae388c-ca1c-4569-95d7-3d7be2e0b8ba

[10] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offprem/saas&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aFGRGd2VQXiXubhiu0dQhwAAAkQ&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0

[11] https://www.theregister.com/2025/04/30/microsoft_meta_autocoding/

[12] https://whitepapers.theregister.com/