[quote user="Rolf Lindby"]

Pegasus and Mercury share the same file format for storing mail folders (PMM/PMI). If a mailbox is accessed only using POP3 no such folders will be created, but IMAP users are able to instruct Mercury to do so.

[/quote]

Ah! This makes perfect sense (why didn't I think of that!).

We run Mercury v4.8 using POP3, SMTP Client and Relay and IMAP modules, with me as the postmaster. We use our own mail client. We have been using this system for some time without problem, but recently I've started seeing a large number of PMM and PMI files being created in my inbox - typically 10,000 per day. The files are always in pairs: one PMM and one PMI for each file name used. The files are all very small - 1kb. If I open a PMM file with wordpad I see something like this:

Sent                                                                                  ogw2anhl:6E5C:FOL0000D  

The file creation is not triggered by any particular event (ie not triggered by new mail being received or sent) and are typically created in batches of 50 or so at a time. Does anyone have any idea why Mercury would be creating these files and, more importantly, how I can stop it from doing so?

Many thanks

Duncan

.pmm and .pmi files are usually created by Pegasus Mail. They represent mail folders (.pmm) and the folder index (.pmi). When Pegasus Mail is instructed to display the contents of a folder it reads the index which informs it about the sender/subject/date for each message the folder contains.

Which mail client are you using to access the mail store?

Thanks for posting a reply.

We don't use Pegasus or have it anywhere on our network, though we did use it in the past. Our mail client is our own built using SharpMIME libraries. We've been using this for a couple of years without any issue and we haven't made any changes to it (or to our Mercury configuration) recently.

A .PMM file is a Pegasus Mail folder file.  The corresponding .PMI file is its index file.  The .PMM file content you posted indicates that the folder name is "Sent".  I believe the content preceding the ":FOL0000D" is the internal folder ID and of course the "FOL0000D" is the filename of the .PMM/.PMI pair. The fact that there is no additional content indicates that it is an empty folder file (no messages stored in it)

I did not know that any app other than Pegasus Mail could create these files although perhaps a client connecting via IMAP could.  I am not aware of Mercury being able to create these files on it own but I'm far from a Mercury expert so look forward to substantiation or repudiation of that.

That's right. Mercury simply drops the .cnm files (new mail messages), into the account folder. It does not have the ability to manipulate messages or message folders (which are files as described above).

My use of Mercury is restricted to using the same modules you describe. As far as I am aware, there is no way Mercury can do this. As Brian says, Pegasus Mail manages the messages and places them into folders but that is under the operator's direction.

Perhaps someone with programming experience may be able to offer some better ideas about what is happening.

Dear All

Thanks for the various replies.

I've been running Wireshark to track which computer is requesting the files be created and it is definitely being done by our mail server. I've also checked the processes running on the mailserver and it definitely is not running Pegasus. I'm completely stumped with this one! To give you an idea, there were 4,494 folders created between 5.30pm yesterday and midday today. The contect on each of them was the same "Sent......" then an ID and the folder name.

Regards

Duncan

Following Brian's suggestion I investigated whether my phone (connecting via IMAP) was craeting the files and bingo. If I switch off my phone, no files are created. I've tried removing my email account from my phone (Android 6.0.1 and using the native client) and then re-adding it but I get exactly the same issue. Each time my phone tries to synch, 50 or 60 files are created. I don't know why this started. I hadn't changed any settings on my phone since I bought it 18 months ago. But at least we know where the files are coming from.

Duncan

Wow - I guess this is something for the Android developers to look into - some apps update automatically (possibly 'silently' without you realising it has happened), so I wonder if an update has resulted in this behaviour.

Pegasus and Mercury share the same file format for storing mail folders (PMM/PMI). If a mailbox is accessed only using POP3 no such folders will be created, but IMAP users are able to instruct Mercury to do so.