PRB: File Downloader fails to download if the URL contains specific characters

If the file list you feed to File Downloader contains URLs with characters like whitespace, %, # and similar, it fails to load these files.

Cause

Such URLs are not valid from the point of view of the server. They don't conform to appropriate RFCs as they contain reserved characters.

Solution

You should use URL enconding, i.e. replace special characters with their ASCII codes with a prepended percent sign, as described in this wiki article:

https://en.wikipedia.org/wiki/Percent-encoding

For example, space character will become %20, hashtag character (#) will become %24, etc.

NOTE: Certain characters may be forbidden even after being encoded. For example, IIS does not allow plus characters (+) by default. In this case, you should avoid such characters in URLs or change your webserver settings (if possible).