Since the old messages are to be an archive, I propose doing it the simplest way: put the old messages on each PC. Yes, there are fancy ways to make accessible from one platform, but it's messy and problem-prone. Here would be my dirt-simple approach: - if the importexporttools addon is not installed, install on both PCs. - on the desktop PC, highlight each folder to be saved as archive (such as the POP inbox) - then right-click and use the importexport menu to export as mbox - repeat for all folders to be shared from the POP account - on both PCs, in Local Folders, create a new folder for each of the folders you exported. - now, for each saved folder, highlight one of the new local folders, right-click and select the importexport menu to import mbox and select one of the desired saved folders - repeat for all folders - you're done.