User's Outlooksearchindex.vhdx consume a lot of read and write action in file server, which cause the file server out of resource and becomes slow response.

Automatic backup and restore of Outlook search index database is enabled in user's lab. UPM will save a backup of the last known good copy of the search index database which consume a lot of read and write during logon.

Disable Automatic backup and restore of Outlook search index database feature via DDC policy.

https://docs.citrix.com/en-us/profile-management/current-release/configure/enable-native-outlook-search-experience.html#automatic-backup-and-restore-of-outlook-search-index-database

 Customer face a very slow logon issue during peak login time. And we can see large write and read action for outlook search in the file server.