Load the old profile and install the '''''ImportExportTools NG''''' add-on. Restart Tbird, then use the additional functions provided by the add-on to export the various folders containing the emails you wish to move to the other profile. For example, assuming the account is of POP type, right-click the inbox folder, select the '''''ImportExportTools NG''''' option then choose '''Export folder'''. If your inbox has subfolders, then choose one of the '''Export folder with subfolders''' options. The first five options in that '''''ImportExportTools NG''''' menu process a whole folder and save ALL the emails in that folder into a single mbox file that you can import into the other profile. These are the options I recommend for exporting a folder and its contents. You will then be prompted to choose a folder where the exported file will be saved. The progress of the export process will be shown in the status bar, so you will be able to tell when the process is completed. Repeat the process for the rest of the folders that you wish to move to the other profile. In the new/current profile, install the same add-on then right-click the target folder into which you wish to import the messages from the old profile (assuming this is a POP account). Select the add-on and choose the Import mbox file option. From there it should be straight-forward. You will be asked to choose the mbox file that you wish to import messages from. Select the one exported from the old profile.