From MSDN, here's a list of characters that aren't allowed:

Use almost any character in the current code page for a name, including Unicode characters and characters in the extended character set (128–255), except for the following:

• The following reserved characters are not allowed: < > : " / \ | ? *
• Characters whose integer representations are in the range from zero through 31 are not allowed.
• Any other character that the target file system does not allow.

From MSDN, here's a list of characters that aren't allowed:

Use almost any character in the current code page for a name, including Unicode characters and characters in the extended character set (128–255), except for the following:

• The following reserved characters are not allowed: < > : " / \ | ? *
• Characters whose integer representations are in the range from zero through 31 are not allowed.
• Any other character that the target file system does not allow.