
If the issue persists, repeat the process and choose Online Repair. This process replaces damaged core files without removing your data or customizations. 21Vianet also expect customer to collaborate at reasonable level accordingly.
⃣ Reset Browser Cookies & Cache
21Vianet understands that receiving timely technical support from qualified professionals is a key aspect of cloud services. Equally important is the critical role that the customer’s IT department plays in the support of its users. The Microsoft 365 operated by 21Vianet technical support team troubleshoots only those issues that are related to Microsoft 365 operated by 21Vianet. Incorrect system time can break your connection to Microsoft’s authentication servers. Always enable Set time automatically and select the correct region in your Windows settings.
Microsoft 365 Apps Crashing After Update — Step-by-Step Repair Guide
- The steps to access the repair tool vary depending on your operating system.
- This guarantees clean configuration files and resolves deep-level corruption issues.
- We provide instant guidance for update errors, installation failures, and Office activation issues.
- Microsoft 365 crashes after updates can be frustrating, but these fixes will restore stability quickly.
- For more self-help resources, see Microsoft 365 operated by 21Vianet.
Assistance for billing and subscription management issues is available online or by telephone during China business hours (Beijing Time), Monday through Friday. Billing and subscription management support can be accessed using the same phone number and online service request process as with technical support. The support telephone number can be found on the
Microsoft Outlook Email Repair Tool Online Microsoft 365 operated by 21Vianet portal. 2 Severity A is only available to customers who signed an advanced online service agreement with 21Vianet through a sales account manager. Download and run the official Microsoft Support and Recovery Assistant (SaRA).
???? Fix Office 365 Login Issues on Mobile
If all else fails, uninstall Microsoft 365 completely, remove remaining registry traces using the Office Uninstall Support Tool, and reinstall it fresh. This guarantees clean configuration files and resolves deep-level
resolve Outlook not sending emails fast corruption issues. Partial updates often break compatibility between Windows libraries and Office binaries.
Step 2 – Update Outlook and Office 365
Go to Settings → Windows Update and install all pending updates. Then open any Office app → File → Account → Update Options → Update Now to ensure both are synchronized. Go
repair PST file without data loss to Control Panel → Programs and Features, select Microsoft 365, and click Change → Quick Repair.

Outlook and Office 365 sync issues can be frustrating but are almost always fixable. Start with basic network checks, enable Cached Exchange Mode, and repair your data files if needed. For persistent problems, rebuild your Outlook profile or use FixTechGuide’s free diagnostic tools to automate detection of authentication and IMAP errors in seconds. The problem usually occurs due to authentication token mismatches, cached credentials, or browser session conflicts. In this guide, we’ll walk you through every step to fix Office 365 login problems on both Windows and the web version. If your Microsoft 365 suite keeps crashing or you can’t recover lost files, reach out for expert help right away.