EagleFiler does a great job of archiving your email. It’s fast. Search and retrieval is top-notch. However, it keeps your email in native format (.eml) and displays items either in its own window, or allows them to open in your mail program. For me, this avoids the problem I’ve observed of lost data or format that sometimes happens converting an email to PDF. Of course, EagleFiler lets you print an email to PDF if you want to send it to someone else. (I’ve not found a way to covert a batch of email items to PDF.) Besides archiving my email, I store all kinds of personal research, receipts, and log files in the EagleFiler app. It’s a handy program.