The user’s problem is that their settings for the e-mail client are not being saved across sessions. This means that their user profile, which contains their personal data, settings, and preferences, is not being preserved or synchronized properly. To solve this problem, the administrator can deploy one or more of the following options to manage user profiles in Horizon:

VMware App Volumes Writable Volumes: This option allows users to store user-installed applications, data, and settings on a disk independent of the VM. Writable volumes can be attached to desktops along with application packages, and they can isolate the user-installed applications from the system-installed applications. Writable volumes can also be configured to capture specific files and registry keys by using the snapvol.cfg policy file. This option can help users retain their e-mail client settings on a writable volume that is attached to their desktop at each login.

Persona Management: This option allows administrators to manage user profiles by using a remote repository that stores user profiles. Persona Management synchronizes the user profile between the remote repository and the local desktop at login, logout, and at regular intervals during the session. Persona Management also supports profile redirection, which allows administrators to redirect certain folders in the user profile to a network share or a writable volume. This option can help users access their e-mail client settings from the remote repository or the redirected folder at each login.

VMware Dynamic Environment Manager: This option allows administrators to manage user profiles and policies by using a central share that stores user configuration files. Dynamic Environment Manager captures and applies user settings and preferences based on conditions and triggers, such as location, device, or application launch. Dynamic Environment Manager also supports profile archives, which allow administrators to back up and restore user profiles on demand or on schedule. This option can help users apply their e-mail client settings from the central share or the profile archive at each login.

The other options are not valid options for managing user profiles in Horizon:

Roaming Profiles: This option is a native Windows feature that allows users to access their user profile from any computer in a domain by storing it on a network share. However, this option is not recommended for Horizon because it can cause long login times, profile corruption, and data loss due to its synchronous and overwrite behavior. Roaming profiles are also incompatible with instant clones and linked clones.

Flexible profiles: This option does not exist in Horizon or Windows. It might be confused with Flex Profiles, which is a third-party product from Liquidware that provides profile management solutions similar to Dynamic Environment Manager.

References: Writable Volumes Overview, Configuring User Profiles with Horizon Persona Management, VMware Dynamic Environment Manager Overview, and [VMware Horizon 8.x Professional Course]