Microsoft has issued a set of instructions for users encountering crashes with the classic Outlook client in Microsoft 365. Users have reported the app crashing immediately or when running in Safe Mode. These incidents can be traced by finding Event 1000 or Event 1001 in the Windows Event Viewer, linked to the error code 0xc0000005 from the ucrtbase.dll module.
Impact and Troubleshooting
Feedback from users points to the problem being exclusive to Office 365 accounts. Usual troubleshooting like reverting to a previous build, setting up a new Outlook profile, or reinstalling Windows hasn’t resolved the issue. Microsoft identified that corrupted client and server mailbox rules in Microsoft 365 accounts are the cause. According to the company, “After updating to Version 2407 Build 17830.20138 or higher, Outlook may close unexpectedly at startup, and this issue persists even in Safe Mode.”
To mitigate the issue, Microsoft advised users to delete all email rules linked to their accounts. This can be done by closing Outlook, right-clicking the Windows Start button, selecting Run, and executing ‘Outlook.exe /cleanrules.’ If the problem remains, creating a new profile is suggested. Users can do this by holding the Shift key while launching Outlook and following the Profile Picker prompts. Email rules can also be manually deleted using Outlook Web Access if necessary.
Other Current Issues and Solutions
Microsoft has addressed additional problems affecting Microsoft 365 users. For those unable to sign in or add Gmail accounts in classic Outlook, users have encountered errors such as “This browser or app may not be secure.” Microsoft suggests trying another browser and ensuring IMAP is active in Gmail settings. Google removed the IMAP toggle in June 2024, making IMAP access always on.
For an immediate fix to the Gmail sign-in issue, Microsoft recommends switching to Office Insider. To do this, create or edit a registry entry (insiderslabbehavior REG_DWORD set to ‘1’) under HKEY_CURRENT_USER\Software\Policies\Microsoft\office\16.0\common. Users should then restart Outlook and select ‘Update Now’ under File > Office Account > Update Options to switch to Microsoft 365 Insider.
In April, some users faced issues where Gmail marked emails from specific Outlook.com domains as spam. Google suggested that Microsoft adjust to new bulk sender guidelines to enhance email delivery to Gmail accounts. Since then, Google’s stricter spam standards have affected bulk senders who don’t meet these guidelines.
Last Updated on November 7, 2024 3:15 pm CET
