"Exchange is in recovery mode" is an ambiguous error that can be difficult to diagnose. It could indicate that...
Microsoft Outlook is detecting differences between cached data on the client machine and data stored on Exchange Server. But an "Exchange is in recovery mode" error could also signify misconfigured DNS settings or an Active Directory issue. This SearchExchange.com troubleshooting guide will help you pinpoint and fix "Exchange is recovery mode" errors in your environment.
|Potential Cause Cached Exchange mode|
|Potential Cause Domain Name System (DNS) failure|
|Potential Cause Active Directory|
Related information from SearchExchange.com:
|Fast Guide: Troubleshooting Exchange Server Event IDs|
|Learning Guide: Exchange Server backup and recovery|
|All-in-One Guide: Exchange Server backup and recovery|
|Reference Center: Exchange Server administration tips and resources|