EFT Server, the Web Transfer Client, and the Plain-Text Client (PTC) follow the standard Windows naming conventions, with a few exceptions (such as no support for Unicode characters).
For example:
You can name files using almost any character for a name, except for the following reserved characters:
< > : " / \ | ? * %
The maximum length for a path is 255 characters. This limitation includes the drive letter, colon, backslash, directories, subdirectories, filename, and extension. If the relative path is too long, a warning message appears.
Characters that are valid for naming files, folders, or shortcuts include any combination of letters (A-Z) and numbers (0-9), plus the following special characters. (Unicode characters are not supported.)
|
^ Accent circumflex (caret) & Ampersand ' Apostrophe (single quotation mark) @ At symbol { Brace left } Brace right [ Bracket opening |
] Bracket closing $ Dollar symbol € Euro symbol = Equal sign , Comma ! Exclamation point - Hyphen |
# Number sign ( Parenthesis opening ) Parenthesis closing % Percent . Period + Plus ~ Tilde _ Underscore |
The Plain-Text Client (PTC) uses a form-based upload in a browser which, for security reasons, won't allow the file name to be modified after the user has selected it via the file browser dialog. The server expects file names to be URI encoded; to encode the file name so that %% makes it to the server, the client would have to modify the file, which isn't allowed. Therefore, if a file name contains %%, upload of that file to the server will fail. (Downloads of files named with %% work, because EFT Server can modify the name.) If you want to upload files with a double percent %% in the file name, use the Web Transfer Client (WTC) instead of the PTC.
For more information regarding file-naming conventions, refer to the Microsoft Windows Developer Network article Naming a File and the Microsoft TechNet article How NTFS Works.