Hi @Ingvar Gustafsson
Welcome to our forum!
Please kindly understand that the Outlook tag here we mainly focus on general issues about Outlook desktop client.
Based on my search, interferences.xml is a file that Outlook 365 uses to keep track of data uploaded from the .ost file to Office 365. It is created when you shut down Outlook and deleted when Outlook catches up with the data synchronization.

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