Steps to Reproduce: 1.Open mail folder tree 2.right click on folder and click "new subfolder" 3.Enter "Con" omit parenthesis and click OK * local folders - first click to create subfolder has no visible response, and no folder created on disk - second click to create subfolder results in a dialog with "A folder with that name already exists", as if the folder had been created. erratically, the error console willl have Timestamp: 12/3/2012 12:40:21 PM Error: Component returned failure code: 0x80550013 [nsIMsgFolder.createSubfolder] Source File: chrome://messenger/content/folderPane.js Line: 2012 * imap folder - i get absolutely no feedback Seems like the failed folder creation isn't propagated back up to the UI.

in the imap case, activity manager has ... The current command on 'aux' did not succeed. The mail server ... responded: Can't get the status ... no such mailbox

It looks that bug 312265 has been changed to this bug.

Interesting. We should report this failure to the user properly. There may be various reasons why a folder wasn't created. We also excluded the special 'aux', 'con' and similar "filenames" to be the target of the profile folder. And we report those invalid paths, in bug 577775.