Does your r2-config have a hidden file extension? On windows, the default behavior is to hide common file extensions such as .txt. Also, if you copied it from the device to the tftp server, it propably appended a file extension in addition to what you named it. I would check the file properties in the TFTP root directory.
Switch#copy run tftp://192.168.41.221
file name? <<<switch will give you an name, mine gave me switch-confg
Yes, file is copied in c:\tftp
Switch#copy tftp://192.168.41.221/switch-confg running-config
Destination filename [running-config]?
Loading switch-confg from 192.168.41.221 (via Vlan1): !
[OK - 1494 bytes]
1494 bytes copied in 12.432 secs (120 bytes/sec)
*Mar 1 00:22:35.901: %SSH-5-ENABLED: SSH 1.99 has been enabled
*Mar 1 00:22:37.335: %PKI-6-AUTOSAVE: Running configuration saved to NVRAM
*Mar 1 00:22:38.241: %SYS-5-CONFIG_I: Configured from tftp://192.168.41.221/switch-confg by console
*Mar 1 00:22:39.860: %DHCP-6-ADDRESS_ASSIGN: Interface Vlan1 assigned DHCP address 192.168.41.106, mask 255.255.255.0, hostname Switch
switch-confg file is not-read only, admin has full controll, others write, read.
make sure your tftp is running as Admin, firewall lets you copy to and from.
what Windows is that ? what tftp server do you use?