[Up]: Storage API : Name Restriction
Names for file and folders cannot be empty, too long, or contain unacceptable characters.
Accepted characters are:
Any other character is unaccepted.
The maximum length of a name is 255 chars.
But names cannot begin with "." (period), "-" (hyphen). Example: ".newfolder", or "-testfile"
Names also cannot begin with spaces or contain trailing spaces. Spaces is to be used within a name only.