Hello Rob, please note this is not an official way how to backup your data, but if you’ve backed up your original user/AppData/Roaming/eM Client folder e.g. the database folder or it’s whole content all you should have to do is to replace the directory with the current database in the user/AppData/Roaming folder which should allow you to see all your previous data from the database files.
However note that in order to restore successfully you have to use the built-in backup and restore option under File > Backup, which will create a database backup file, that you can restore from.
I tried this but it doesn’t seem to work. Prior to opening emClient, I copied over the .dat files that I had saved from the old computer into the new emClient folder, but when I open emClient, the emails don’t show up.
if you still have access to your old computer, I recommend going back to it and backing up your data correctly.
If you can’t do so and these .dat files are your only copy, then I’m sorry to inform you that they might be corrupted and you probably lost your data.