I've had this trouble before and I don't remember finding a resolution. I searched the forum and couldn't find an answer either. Subtle differences in wording leads to similar yet very different problems.
My issue is I had a site to site connection with 3 UT servers and OpenVPN and all was well. One server (hardware) crashed in a storm and had to give client disti of OpenVPN to one staff member. Installed, gave admin pass (I hate this) so OpenVPN can run properly (W7 elevation) and it connects fine and he can access what he needs in this office.
What he cannot do if the VPN is connected is anything on his subnet - print - ping anything.
My subnet is 192.168.2.0/24 his is 192.168.0.0/24. I know they should be less "homelike" subnets and I have started changing them (third subnet is 10.10.10.0/24) but I haven't gotten them all changed yet. Still it works fine site to site with these. It is only when client connects that it is an issue. He has to disconnect the VPN to print and sometimes needs to restart beore he can print.
Any help you can lend will be appreciated.