Appendix > Reserved file name characters

Without getting too deep into the weeds about the details of various operating systems and file systems, file names may not contain the any of the following characters:

•< (less than)

•> (greater than)

•: (colon)

•" (double quote)

•/ (forward slash)

•\ (backslash)

•| (vertical bar or pipe)

•? (question mark)

•* (asterisk)

Further information

https://www.boost.org/doc/libs/1_36_0/libs/filesystem/doc/portability_guide.htm

https://learn.microsoft.com/en-ca/windows/win32/fileio/naming-a-file