matt this worked 100% for me as an example; the difference here is I used the username parameters for the net use as a user that has permissions on the network;
from there, i got an error on adding the filegroup, until i set the trace flag:
exec master.dbo.xp_cmdshell 'NET USE J: \\DEV223\c$\DataFiles /user:disney\lizaguirre NotTheRealPassword /persistent:yes'
ALTER DATABASE [SandBox] ADD FILE
( NAME = N'TESTING',
FILENAME = N'J:\TESTING_Archive.ndf' ,
SIZE = 3072KB ,
FILEGROWTH = 10%)
/*
Msg 5110, Level 16, State 2, Line 1
The file "J:\TESTING_Archive.ndf" is on a network path that is not supported for database files.
Msg 5009, Level 16, State 8, Line 1
One or more files listed in the statement could not be found or could not be initialized.
*/
DBCC TraceON (1807)
ALTER DATABASE [SandBox] ADD FILE
( NAME = N'TESTING',
FILENAME = N'J:\TESTING_Archive.ndf' ,
SIZE = 3072KB ,
FILEGROWTH = 10%)
/*
Command(s) completed successfully.
*/
Lowell