Thank you for inquiry.
If a folder contains special characters like you mentioned above, then ImapFolderInfo.Name does not handle these special characters and display junk characters instead. I have verified this issue and logged this bug (ID: 29127). We will look into it and will inform you when it gets fixed.
But, if a message contains these special characters in subject, then ImapMessageInfo.Subject gets and displays the correct characters. I tried with latest release v6.6 and could not reproduce this with the email messages. Below is my code for your reference.
ImapFolderInfoCollection folderInfoColl = client.ListFolders();
foreach (ImapFolderInfo folderInfo in folderInfoColl)
Console.WriteLine("Folder: " + folderInfo.Name);
// get the folder with special characters - bug here
if (folderInfo.Name.Contains(“placement”) == true)
// list messages from this folder
ImapMessageInfoCollection msgInfoColl = client.ListMessages();
foreach (ImapMessageInfo msgInfo in msgInfoColl)
Console.WriteLine(msgInfo.Subject + " = Date: " + msgInfo.Date);
if (msgInfo.Subject.Contains("Déplacement ") == true)
MailMessage message = client.FetchMessage(msgInfo.SequenceNumber);