Version: 1.9.5 (using KDE KDE 3.5.5) Installed from: Gentoo Packages OS: Linux When I access IMAP messages in my Inbox outside of KMail, i.e. with Thunderbird, Horde, or SquirrelMail, the "new" status is maintained across clients. If I read a message in SquirrelMail, for instance, it doesn't then show up as a new message in Thunderbird -- it shows up as a read message. KMail does things differently and shows all messages that are new to KMail as new messages, regardless of whether they've been read. This is annoying and also obfuscates which messages are really new that I haven't seen before and which ones aren't. This only happens in the Inbox. Messages that have been moved to another folder from a different client, i.e. from filters, do not then show up as new. The correct new counts are shown for those folders.
I can confirm that on kubuntu, KMail 1.9.6 (enterprise 0.20070831.706792). Using the "Refresh Cache" option in the Troubleshooting IMAP cache dialog will cause ALL mail in the inbox to show as unread. This is on a disconnected imap account.
Thank you for taking the time to file a bug report. KMail2 was released in 2011, and the entire code base went through significant changes. We are currently in the process of porting to Qt5 and KF5. It is unlikely that these bugs are still valid in KMail2. We welcome you to try out KMail 2 with the KDE 4.14 release and give your feedback.