Firstly we need to talk about POP. Back in the old days, POP used to rule the world. It’s the simplest of the protocols and yet one now most likely to cause you any number of problems if you have any more than one computing device. By the way, POP stands for Post Office Protocol (pay attention there will be a test).

"That’s easy" you say. "If POP is evil I will just make sure I never use it when setting up email on my fantastic new iPad".

Nope. If POP has ever been used to access your email on any computing device, you are likely to have problems. To understand why and how to fix it, we need to talk about how it works and how it messes up. Some of this might look a little technical if you are not used to such things, but the true is, its just messages being past from one place to another. Follow the steps through with me and you will see any glaze of complexity is just there to help geeks impress people with their knowledge. Under a thin layer of jargon its all very simply really.

Let’s says that hard working top student Alice, wants to send an email to her grumpy old dad Bob:





She sends it, he receives it. Nothing remarkable there, happens trillions of times a day all over the world.  Better get on to the next topic. No hang on, that’s not it at all, we need to talk about what is happening under the covers to understand a) why that can get you in a muddle and b) how to avoid said muddle.




Alice sends an email:

It arrives in Grumpy Bob’s Hotmail account:

What we are looking at here is the Hotmail webpage. I've used Hotmail as an example because it is popular and everyone has heard of it. There are any number of other email systems, but the principles are exactly the same.

We are looking at Grumpy Bob’s email by starting up a web browser, going to the Hotmail website and logging in. That gives us a window into exactly what Hotmail are storing on their servers. Its known as webmail if you access your email in this way. However, lots of folks, Grumpy Bob included, don’t get their email by going to a webpage. They use a program on their computer that goes and gets the email. That’s were the problems start.

Bob is way too grumpy to spring for nice shinny new iPad. He uses a 12 year old desktop PC with a 12” screen running Windows XP and Outlook Express, its hideous and its just like your grandma used too (before she upgraded 5 years go and took up snowboarding). His settings look like this:

Notice that that is says his incoming server is a POP3 server (sometimes this is written as POP and sometimes POP3, it’s the same thing for our purposes). That's the type of protocol used for this program to talk to the server (if you have no idea what I talking about at this point, have a look here and all will become clear).

In his email program he sees the email from the lovely Alice:

But if we go back to the Hotmail webpage again:

Where did that email go? An answer is in the advanced settings of the Outlook Express:

Notice how the box to "Leave a copy of the message on the server" is not ticked. If you are not leaving it on the server, you are taking it off the server. It gets deleted by Outlook Express and that’s the default. If you don’t tell it to do anything else, that what it does.

This used to work fine in the old days when we only had one computer and the storage limits on the server were very low. You had to take emails off of the server and store them on your computer, or you would run out of space on the server. It's not like that any more. Now we have high storage limits and multiple devices. For things to work we need our email programs not to delete emails from the server and greedily keep them for themselves, we need them to keep a local copy of whats on the server, to keep everything in sync. POP simply does not work that way.

Now, lets suppose that a miracle happens and Bob goes and buys an iPad. The nice lady in a blue shirt sets up his email on the iPad in the shop. Bob is slightly less grumpy because emails are appearing. Bob begrudgingly uses is new iPad for a few days, until he wants to look up something on the PC. When he’s done that he goes back to the iPad and… all the emails have disappeared! Bob is even less happy than usual.

What the hell just happened! Outlook Express read the emails and then deleted them from the Hotmail server, just like it always does. Outlook Express is clearly evil and should be purged from the face of the earth at once! Only, no. This behavior is not unique to Outlook Express. Most email programs have an option to delete from the server, many even have it switch on by default when working with POP (Hotmail even has an option to say ignore a POP program that asks it to delete emails). But that’s not the point, because its a special case, most email accounts don't have this ignore switch and we need to cover the principle of how all email works here).

Lets say, for example, that you setup your email program to leave the email on the server and left it running. You will be downloading emails into you email program, deleting the ones you don’t want, filing other in sub folders, sending replies. All sorts of tasks to get things the way you want them. The tricky part, is that’s a one way conversation with the server. All those changes you are making are not being sent back to the server. If you go and look at the webmail all you will see is ever growing list in the inbox.

What happens when you current computer breaks or becomes too unfashionable to use any more? You get a new one and you point it at the server. At which point the 10,000 emails that you have received in the last few years all come tumbling down onto you new device. No sub folders, no deleted, no nothing. Not nice.

It doesn't matter that you have diligently deleted or filed them all as they came in. There are all coming back in one great lump. You won’t know this as you are going along it will all just happen when you get your new system, so you need to plan ahead.

This is just one example of how POP can work just fine when you have one computing device and then mess up all over the place as soon as you have more than one.

So what are you going to do? You are going read the article on moving from POP to IMAP, that will save you.