Windows' UAC setting can prevent FastCAM from updating its temporary files in the FastCAM Folder.
Users who experience this issue will find that upon restarting FastCAM or FastNEST, their previously changed settings have been reverted to an earlier "default". This is because the temporary files that hold saved settings could not be updated.
You can disable the UAC, which causes this issue, by following this guide:
However, if that is not appropriate for your environment, you can configure the FastCAM Shortcut to run "As Administrator"
1. Right click on FastCAM shortcut
2. Left click on Properties in the context menu
3. In the Shortcut Properties window left click on "Advanced"
4. In the Advanced Properties window enable the check box "Run As Administrator"
5. Left click on "OK" to close the Advanced Properties window.
6. Left click on "OK" to close the Shortcut Properties window.
7. Repeat steps 1-6 for your FastNEST and FastPLOT shortcuts
On the next start of FastCAM with this shortcut Administrator access will allow updating of the temporary files.