Hi @Matlock67 ,
Thanks for your feedback above which shared more information and glad to know that your issue is resolved now! Since our forum has the policy that The question author cannot accept their own answer. They can only accept answers by others, and according to the scenario introduced here: Answering your own questions on Microsoft Q&A
I would make a brief summary of this post so that other forum members could easily find useful information here:
[Activating lagged copies - Summary]
Issue Symptom:
Outlook Calendar List view - Duration field stopped calculating
Solution:
Perform an advanced search, then add the duration filed:
Step1: Search Tools> Advanced Find
Step2: Type test in Search for the words box and click on Find Now.
Step2: Right-click on any field and select Field Chooser, drag Duration to add a column.
Step3: The search is complete:
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