Is it necessary to reboot a pc for a changed devicepath entry to become active.

The registry entry's in Local machine are only used in the start and logon procedure.
Changing obne of these entry's will only activate them when teh machine is rebooted.

Regards
Erik
www.DinamiQs.com

kind regards,

You can also restart explorer.exe to refresh the registry without a reboot. It's kind of pointless since both methods kill a user and you want to do that off hours. Just an fyi.

settings to apply immediately you can try to make changes both in registry and WMI.
i'm not sure if you have WMI setting for what you need but if they exist , changing them should effect the machine immediately.
the registry will effect in the next reboot...