Hello FB4 IMI,
Thank you for posting in Q&A forum.
You can try to prevent the network drive from being mounted by using Group Policy. You can create a Group Policy Object (GPO) and configure the "Remove Map Network Drive and Disconnect Network Drive" policy setting under "User Configuration\Administrative Templates\Windows Components\File Explorer".
You can then apply this GPO to the OU where your FSLogix test users are located.
After you configure the GPO, sign out and sign in the user account in OU, or run gpupdate /force for the signed user in the OU. At last check the result.
I hope the information above is helpful.
If you have any questions or concerns, please feel free to let us know.
Best Regards,
Daisy Zhou
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