POP3 redownloads

[Mwoplock]

Yesterday a number of our outlook mail clients started to lose track of messages they already downloaded. Each time a send and received was done, in most cases one or two old messages would redownload. In once case, the persons entire email history redownloaded.

The system has only been running for a few months now with about 20 users. It runs on a dedicated Windows 2008 server with 1 TB of disk space (which is way underutilized)

Also, we have now received two PDF files that were corrupt. Never happened before

I'm worried something is getting corrupted. Is there some daily maintenance that needs to be done?

Any thoughts would be appreciated.

[Mwoplock]

I've checked and the PDF files are not corrupted when using webmail. So something is going wrong with the transfer between the server and outlook. However viewing the PDF on an iphone (using IMAP) also will not display. Ugh....

[Code Crafters]

POP3 is mainly meant for downloading locally to one mail client (e.g. outlook) then deleting from the mail server. If you want to leave messages on the server, even though POP3 can do this you should really use IMAP4 as this works just like WebMail with multi-folder on-server storage of emails and should resolve the problems you're having. Also, make sure no antivirus software is interfering with the downloaded PDFs and corrupting them as if they work on WebMail it must be being corrupted on download by loss of connection, antivirus or something similar.

[Mwoplock]

We use eset antivirus. I had the email server running eset and setup it up as per your instructions. Once I disabled the eset, all corruption went away. I like the idea of the server running the software, but obviously, at least for me, it can't be done.

[Code Crafters]

You can run an antivirus on the mail server but you have to disable email scanning as this is intended for a client like outlook not for a mail server and will disrupt email communication too much.