Version:           1.13.5 (using KDE 4.5.1) 
OS:                Linux

* copied a huge mail tree from an IMAP account to local folders
* deleted the original tree in the original IMAP account.
* moved the tree from local folders to a second IMAP account.
* added a third IMAP account in the KMAIL account config

ERROR:

Kmail starts doing something (before closing the account setup dialog box) and discovers that the local imap cache contains references to folders that were moved. The folders are not found (because they were moved,) so Kmail emits the following error message, for each folder, in a dialog box with an OK button:

Error opening [...]; this folder is missing.

There is no "OK TO ALL" option in this error message and, as it happens, there were a few hundred folders in the tree that was moved. So I've been here for a long time now pressing the escape key to get rid of these error messages.

Reproducible: Always

Steps to Reproduce:
This problem appears in many contexts. Normally only a small number of folders are reported missing from the local cache so it's easy to ignore the messages. In this case I am moving trees with hundreds of folders and it is suddenly a severe problem.

Actual Results:  
Useless error message for each folder that was moved (See ERROR above.)

Expected Results:  
The code that moves the folders should be smart enough to invalidate the local cache information for each folder that is moved. This would prevent all the error messages that appear in so many contexts due to invalid cache information.

If fixing the folder move code is not easy to do there is another option:

The code that reports the cache error for the missing folder can be improved to include an "OKAY TO ALL" button. Pressing this button should cause the current operation to not report any remaining missing folder errors.