Push all traffic through OpenVPN
Sometimes the users home network is the same as the remote network (typically if the office is on a 192.168.0.x or 192.168.1.x range), which then means that the PC will not route any traffic through the VPN as it thinks the remote destination is on the local network.
Fortunately with OpenVPN we can work around this by adding a single line to the config file to push ALL traffic through the VPN whether it's destined for the remote network or not. This has the unfortunate side effect of making anything on the local network unavailable while the VPN is connected though, but there is no other way around the issue, short of changing the entire IP addressing setup of the users home network.
Locate the OpenVPN config file in use:
Once you've identified the path to the .opvn file, open notepad as administrator and navigate to the file in question. Once it's open in notepad, add the following line to the bottom of the file
redirect-gateway def1Save over the current config file (make sure you don't just save it as a txt file) and reconnect the VPN, no need to restart the OpenVPN client.
Once connected, the user should have access to everything on the remote network.