Hi JH Lu,
Thank you for posting your question in the Microsoft Q&A forum.
Based on your description, the Search options are greyed out because Outlook cannot use Windows Search to index your mailbox. This usually happens when the Windows Search service is disabled or Outlook is not included in the indexing list. Below are the steps you can try:
1. Enable Windows Search Service
- Close Outlook > press Win + R, type
services.msc, press Enter. - Find Windows Search, set Startup type to Automatic (Delayed Start), and click Start if not running.
2. Ensure Outlook Is Not Running as Administrator
- Right-click Outlook shortcut > Properties > Compatibility tab > uncheck Run this program as administrator.
3. Add Outlook to Indexing and Rebuild Index
- In Outlook: File > Options > Search > Indexing Options > Modify > check Microsoft Outlook > OK.
- In Indexing Options: Advanced > Rebuild, then wait until indexing completes (check Indexing Status in Outlook).
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