To export your emails to .eml files, Click File -> Export in the main menu and following window appears:

Choose the Export to .eml files option and click Next.

Check all the items you want to export from your eM Client and click Next.

You can change the default location to save the exported .eml files by clicking the Browse button and select the desired destination directory. Click Finish to finish exporting your email contents.
Backing up eM Client data files
You may wish to back up eM Client's data files, that include all the emails, calendar events, contacts, tasks and configurations. However, these data files can only be restored in eM Client.
You can find the data files in C:\Users\\AppData\Roaming\eM Client\ if you are using Vista or newer versions of Windows; or C:\Documents and Settings\\Application Data\eM Client\ if you are using XP or older versions of Windows.
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