FTP: 550 Cannot STOR.
If your Windows FTP is working correctly, but some users are reporting "550 Cannot STOR." errors.
It may be a good idea to check your logs for the filenames they are using.
We encountered the same problem on one of our shared Windows servers.
The problem was an illegal filename.
The user was using a mac computer, which allows a filename to contain ":".
The ":" is an illegal character to Windows and will finally result in a "550 Cannot STOR." error.
