It's important that users run the most recent version of their Outlook client for full functionality and correct behavior. For information about the minimum required versions of Outlook in an Office 365 environment, see Outlook Updates.
For information about monthly updates and the corresponding build numbers, see Outlook and Outlook for Mac: Update file versions.
If additional investigation and collaboration with Microsoft is required, collect the following details from pilot users:
- Approximate number of times a user was prompted for credentials
- Approximate number of users who report this issue
- After the user enters their credentials, can they successfully connect to Exchange by using their original profile?
- Is the user prompted after the client first restarts, or do they continue to be prompted intermittently?
Office Configuration Analyzer Tool (OffCAT)
OffCAT will provide details about the client version and Outlook-related registry keys. Common issues are related to old client versions and Autodiscover. IT administrators should review the issues list to help troubleshoot the cause of authentication prompts. If no related issues are discovered, the report should be sent to Microsoft for further analysis as part of the collaborative investigation.
Outlook troubleshooting logs
If users continue to be prompted intermittently for authentication and credentials, Outlook troubleshooting logging should be enabled. These details are important for any Microsoft investigation of this issue.
If users are no longer prompted for their credentials, the next group of pilot users should be contacted to proactively enable Outlook troubleshooting logging before their migration. An OffCAT report and the ETL files from the %temp%\Outlook logging folder should be provided to Microsoft for the collaborative investigation.
Depending on the information obtained from the OffCAT and Outlook troubleshooting logs, additional diagnostic information may be requested. This may include a fiddler trace. If this is required, Microsoft will send a diagnostic package to let users securely capture and upload the results of the trace.
Article ID: 3187952 - Last Review: Aug 29, 2016 - Revision: 1