With 4:4.5~20100920.1177660-1maemo1.1177547 , deletion of an "imcomplete account" (i.e. an account that showed up as "Kolab" + "demo.kolab.org") left the account "alive" in the tree view. Folders could be selected and showed the contained emails etc. In the flap however, in the Accounts section, the Account did not show up anymore. After restart of the application, no accounts showed up in the tree view anymore (not even the "Local Folders"). I am relatively sure that a similar action with the same version succeeded before, thus the "sometimes" in this issues title.
The "Local Folders" reappeared in the treeview after a reboot of the device.
Could you give more steps for how to reproduce this? I don't know what an incomplete account is. And when you restart the application you see no accounts at all until you reboot? Your update is that after rebooting, the bug is gone? Can you try manually restarting Akonadi instead of rebooting and see if that has the same effect? (akonadictl restart)
The folder list being empty issue has been fixed quite a while ago already. The rest is not reproduceable anymore either.
I am closing this bug as a duplicate of 262177 (Deleted IMAP account still shown) although there might have been additional issues this problem is gone for good atm. *** This bug has been marked as a duplicate of bug 262177 ***