How to deal with characters like ":" or "?" that make invalid filenames?

I just tried to move a directory containing music files with thunar 4.10 It complained that a file name was invalid. It turned out that one file name (song title) contained a question mark. I suspected that this was a problem, removed the question mark and could indeed copy the file. Adding the "?" back in was not possible. I also tried it with rename on the command line but that didn't work either. (not sure what thunar uses under the hood, so this test might be moot) Now if a question mark makes the file name invalid, how could this file be created in the first place? I created the files with SoundJuicer from a newly obtained CD. I was able to play the file (with "?" in the name) in various players. What's going on here? Can I have the "?" in the name or not? Why is the file manager unable to handle such files while other applications seem to be ok with it? **Update:** Next song has a ":" in it. Same problem as with the "?". > These are not invalid characters to Unix; typically only the NUL character and the / character are invalid filenames (the / being the directory separator). This was what my intuition told me as well, because I never had any issues with file names in Linux and could throw pretty much everything sensible at it and it worked ok. This is what motivated the question here. I never encountered invalid file names before. > Were you trying to move the files to a USB stick? If so, is that stick formatted as FAT32 or as a native Linux filesystem? The target is indeed a USB stick that I bought today. I opened gparted and it is formatted as FAT32. I'm not exactly sure but that's a Windows thing right? And Windows has a bunch of characters that it doesn't support, apaprently including ? and :. Am I right?