"Folder Internal Data" - How can i get this to go away?

[aphexii]

After checking my e-mail using roundcube webmail, the next time i check my e-mail using a regular program (outlook, thunderbird), i get an e-mail with the following "DO NOT DELETE THIS MESSAGE - FOLDER INTERNAL DATA" and it says;
"This text is part of the internal format of your mail folder, and is not
a real message. It is created automatically by the mail system software.
If deleted, important folder data will be lost, and it will be re-created
with the data reset to initial values."

Its starting to get annoying, any ideas how I can make this stop?

[bpat1434]

What email system are you on?

[aphexii]

What email system are you on?

Not sure if i fully understand what you mean by 'email system' as i'm fairly new using my first VPS.

The server shows; vm-pop3d

[bpat1434]

If your server is POP (which yours shows it is) and only POP, then Roundcube won't work. Roundcube only does IMAP servers right now. So, the question is what email server software is your server running? A few examples can be found around this site, but some of the more common ones:

Courier IMAP
Cyrus
Exim

You might try telnetting into your IMAP server and it should tell you the type of email server it's running. Usually, upon connection you get a line that looks like:

* OK [CAPABILITY IMAP4rev1 UIDPLUS CHILDREN NAMESPACE THREAD=ORDEREDSUBJECT THREAD=REFERENCES SORT QUOTA IDLE ACL ACL2=UNION STARTTLS] Courier-IMAP ready.

What is bold & green is typically your email server.

NOTE: To telnet to your server, do:
telnet imap.servername.com port