The Updater cannot write new files to the hard drive; settings reset after reloading.
First, an exclusion for the FGU installation directory should be added to any installed security software (i.e. Windows Defender, Kaspersky, F-secure, etc..). This will prevent the security software from removing the required permissions again.
To restore the required permissions on the FGU installation directory:
Open file explorer and browse to the FGU installation directory (default is C:\Program Files\SmiteWorks)
Right-click on the Fantasy Grounds folder and click on Properties
Click the Security tab
Look in the Group or user names list for the Users group
In the very rare occurrence that there isn’t a Users group already listed, do the following: Click the Edit button, then click the Add button Type in Users and click Check Names and then click OK
6. Click to select Users in the Group or user names list, then check the Full Control checkbox under the Allow column. Once done, click Apply at the bottom.
7. Relaunch Frounds Unity and try to update or save settings.