A Summary Task name that contains a slash or backslash cannot sync with a SharePoint server

There are many special characters that cannot be used in the name of a folder on SharePoint. In most cases, SharePoint Workspace checks for these characters when you save the form to create a folder. However, the Summary Task is a special case. Although a Summary Task is structurally a folder on the server, SharePoint Workspace treats it as a list item and does not check that the characters in the task name are valid for a folder. When SharePoint Workspace sends the Summary Task name to the SharePoint server, the server cannot create the folder and responds with an error. You receive the error message that corresponds to that error when you click Resolve Conflict or Error.

If you use an invalid character other then the slash or backslash in the name of a Summary Task, SharePoint will return an error that explains that the name contains characters that are not permitted. However, the server interprets a slash or backslash as part of a path and not as an invalid character in the folder name. Because of this ambiguity, the error message for a slash or backslash is less clear than the error message for other invalid characters.