SUMMARY STEPS TO REPRODUCE 1. create a mbox account to use linux mail utility ("mail" command) 2. 3. OBSERVED RESULT If someone sends a mail then it is well in the mbox but kmail indicates 0 mail , storage size 0 and displays no mail. EXPECTED RESULT If someone sends a mail then kmail displays the mail SOFTWARE/OS VERSIONS Windows: macOS: Linux/KDE Plasma: (available in About System) KDE Plasma Version: 5.19.4 KDE Frameworks Version: 5.73.0 Qt Version: 5.15.0 ADDITIONAL INFORMATION kde apps 20.08.0 I tried to recreate the mbox account but problem still there. It's a recent problem till these days no problem. Perhaps the update to 20.08.0 ?
I can confirm this issue on Kmail 5.15.1 and KDE Frameworks 5.74.0. Kmail doesn't show the e-mails of a mbox mailbox in /var/spool/mail.
today i get a good news. kmail displays the list of the mails but only when clicking on the account not when clicking on the corresponding favorite. i created again the favorite then no more problem with mbox account. Perhaps the update to kde frameworks 5.75.0 and plasma 5.20.0. I am not sure.