I've seen parts of this bug mentioned in other bugs (267890, 232634) but described like this. Bottom line: renaming a folder to back to a name it had before causes problems. Steps: 1. make a folder (folder1) and put some messages in it 2. rename it to folder2 In the profile directory, the files folder1 and folder1.msf disappear but directory folder1.sbd does not, folder2, folder2.msf and folder2.sbd appear but folder2 does not contain any messages. 3. rename folder2 to folder1 Now, in FB folder1 is empty, in the profile directory all files and directories for folder1 and folder2 exist and folder1 contains the messages. 4. exit FB and start again Now, in FB you have folder1 which does not contains messages and folder2 which does. In the profile directory it is the other way around. 5. delete folder2 In the profile directory, folder1 disappears with all the mails in it! folder2 remains. Tested with Firebird 1.0 (official release) on WinXP.

DUP of Bug 65303. If you use more names in rename, you can enjoy more funny result. See my test result in Bug 65303 Comment #30. *** This bug has been marked as a duplicate of 65303 ***

I can't imagen a cause other than Bug 65303 for original case of Bug 232634. For JavaScript error in Bug 232634, I think a result of Bug 65303. As you see in Bug 65303 Comment #30, relation among folder name/.msf file/folder file is completely corrupted, then any error can occur because access to invalid file will be executed after the corruption. For Bug 267890, it is very similar flaw to this bug. But similar change in different codes may be required, because one is "Create and Rename" and other is "Create and Delete". So we'd better to keep separated bugs.