I've encountered at least twice now a situation where an ACC/BIM360 project name contained an illegal character such as: <>:"/\|?*'
This causes issues when trying to link files in Revit becuase the folder name, which is identical to the project name, is illegal, cauing it to be impossible to navigate to the project folder containing the files.
Obviously, the project name should not be allowed to have such characters, same as how ACC does not allow these characters for any folders- see screenshot below.

