When I originally set up a POP account in Thunderbird for Mac some years ago, my address was at interchange.ubc.ca, then the POP server migrated to mail.ubc.ca In Account Settings, my e-mail address, POP server name, and Copies and Folders names all reference mail.ubc.ca (as they should). But in my ~/Library/Thunderbird/Profiles/<profileName>/Mail folder, the POP folder is still named pop.interchange.ubc.ca. (N.B. <profileName> is a placeholder for my actual profile name, not displayed here for security reasons) I have many filters set up to move messages to specific folders at the same level as my Inbox in my mail.ubc.ca POP mailbox, but whenever I restart Thunderbird and run a filter, I get the error, "The folder 'folderName' could not be found, so filter(s) associated with this folder will be disabled. Verify that the folder exists, and that filters point to a valid destination folder." (N.B. <folderName> is a placeholder here, for example it might be "Trash") I can then select the destination folder in the "Choose folder ..." dropdown menu and run the filter, but whenever I restart Tbird, I get the same error all over again. In the msgFilterRules.dat file for this account, I see lines like these: "actionValue="mailbox://<username>@pop.interchange.ubc.ca/<folderName>", e.g. actionValue="mailbox://<username>@pop.interchange.ubc.ca/Junk" [N.B. <username> is a placeholder for my actual username I'm wondering if this is due to a mismatch between the POP server name and the name of the POP mailbox folder in the Finder. Is it safe to change the name of the latter to "pop.mail.ubc.ca", and should this fix the problem? Will this automatically update the server name in the msgFilterRules.dat file, or do I have to edit it to replace all references to "pop.interchange.ubc.ca" with "pop.mail.ubc.ca". If it is not safe to do this, or it is unlikely to fix the problem, any advice as to what to try instead would be greatly appreciated! Many thanks!