SQL Server Admin 2014 :: Check If UNC Path Exists (It Is Folder - Not File)

usual way to check if file exists

DECLARE @File_Exists INT
EXEC Master.dbo.xp_fileexist 'serverBSQL_Backupfile.bak', @File_Exists OUT
print @File_Exists
1

And if check folder, can use "nul", but it doesn't work for UNC path

DECLARE @File_Exists INT
EXEC Master.dbo.xp_fileexist 'serverBSQL_Backupul', @File_Exists OUT
print @File_Exists
0

If use xp_subdirs like:

EXEC master.dbo.xp_subdirs 'serverBSQL_Backups'

If the folder doesn't exists, Msg 22006, Level 16, State 1, Line 3 xp_subdirs could not access 'ServerBSQL_Backups*.*': FindFirstFile() returned error 67, 'The network name cannot be found.'

how to check if UNC folder exists in Backup? in my code I want to check if the unc folder exists before doing backup, the unc path is retrieved from other table or backup history.