All of my mail boxes have been in mbox format but I thought I'd try maildir as it's safer in the event of one email being corrupted.
So I set up a mailder box using Balsa and moved the contents of the mbox to it. Fine - I now had 437 emails in the new maildir mail box.
I also use kbiff to alert me to new mails and it told me that I had 437 emails in total with 190 being unread which was nonsense 'cause they'd all been read.
I tried marking them all unread and then all read - nope it still insisted that 190 hadn't been read. From what I understand of the maildir format the individual files were all marked read.
I even, sneakily, altered the value of the unread mails in the kbiffrc file to zero but, no, it still insisted that 190 of them had not been read.
In the end I changed back to mbox format and kbiff is now happy and so am I.
Anyone come across anything like this before?