User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; .NET CLR 1.1.4322) Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.6a) Gecko/20031030 Mozilla Mail -> Local Folder -> You have one like 'UvT Internet en DRC'. I wanted to rename it to 'UvT Internet / DRC' (With '/' instead of 'en'). Renaming it causes the folder to 'loose' all their mails. Restarting Mozilla (that is: close all mozilla related stuff) brings back my original foldername, and mail. Suggestion: disable the '/' character as a valid character for local folders. Reproducible: Always Steps to Reproduce: 1. Mozilla Mail 2. Local Folders 3. You have one folder like 'UvT Internet en DRC'. I wanted to rename it to 'UvT Internet / DRC' (With '/' instead of 'en') Actual Results: Renaming it causes the folder to 'loose' all their mails. Restarting Mozilla (that is: close all mozilla related stuff) brings back my original foldername, and mail. Expected Results: Disable the '/' character as a valid character for local folders. I bet it's because of the Windows' filesystem that there can be no '/' character in a foldername. But Mozilla tries to rename it, however the actual folder isn't renamed. So, 'catching' illegal characters would prevent this from happening.

*** This bug has been marked as a duplicate of 89986 ***

verified.