It usually appears in a cross-platform synchronization and appears on Windows Agents. Basically means what it says - the peer that is supposed to download the files cannot do it because the file system does not support some of the symbols in the filename.
On some occasions the warning itself might not give a hint at what exactly unsupported character is present - the filename on warning text looks correct, like on the example below.
and also looks correctly in FILES tab for the agent, even though has status 'Bad name'
It will require to check the file on source Agent so as find the true filename that is causing the problem.
One of the ways to discover all the files mentioned in the error message, in case there are more than two, is to search through the logs on the agent in the Job run (Job Run -> Logs). Check the trailing space in "AwesomeFile " event.
However, even this is not the true cause. In our example the file itself originates on OS X Agent. In Finder the files looks like it has "?" symbol at the end:
If that was for the question mark, the warning message in the Management Console would have mentioned the question mark. However, the true reason is that is has a line feed symbol. It can be discovered using Terminal app with command mv (use Tab key to autocomplete the filename):
File events must be enabled
Your event log level should be set to "All" to ensure you receive file events.There are two ways to fix it. Either will require to restart a Consolidation or Distribution job; or run folder scan on this agent for Sync job.
1) Rename the file on source. If possible, remove all the invalid symbols in its name.
2) Edit the Agent Profile and set parameter "Resolve filename system conflicts" to Yes. In this case the Windows Agent will replace the symbols with underscore (_) or create filename conflicts. The agent will also publish these events into the event log