Access to the path 'c:\some\path' is denied for MSSQL CLR

I think this is a permissions problem, but I'm having trouble locating it. I have a group of CLRs on one server (SQL Server 2016) and they work as they should. All are marked UNSAFE and they do various types of file I/O (read, write, copy, move, rename, etc.). I can run them via SSMS or from a job with equal ease. I need to install them on another server (also SQL Server 2016). Using the original Visual Studio Project I have deployed them to the new sever. They show up in SSMS. That part looks fine. When I, from SSMS, try to run one I get the following error: "Access to the path 'whatever path I passed in' is denied." I'm logged into SSMS under my windows login. I have permissions to the database, I'm dbo. I'm an admin on the server. I have permissions in the file system. What else could I be missing?