Towards the end of last year we started using Mimecast services, in particular their cloud-based e-mail archiving. Since then we’ve been rolling out the Mimecast Services for Outlook (MSO) add-in.

We’ve informed the users that we will be give them training in the next few months, and we do not require them to use Mimecast, but my boss stated that we are getting rid of Personal Folders (pst files), by putting them into Mimecast. Unsurprisingly this did cause something of a backlash. Though, really, who likes change?

I know the IT reasons for getting rid of Personal Folders (inefficient, unreliable, single access, etc), but from an average user’s perspective, unless they have had one fail on them, they see them as simple and only way to archive e-mail when their 200Mb mailbox is full.

So what can I say to the users, to get them to understand why Personal Folders are not the best solution?

I've read through the comments and answers. You've given me a lot to think about. That is why it has taken be awhile to respond.

First, I would like to make it clear that we are giving the users an alternative. Mimecast, has unlimited storage, remote access and a number of other features, that we are trying to promote to the users.

The 200Mb limit is unlikely to change. And so far upgrading Exchange, from 2003 to 2010, has only been discussed, but is not consider a current priority.

  • 1
    Give them more space before their mailbox is full. I am good at cleaning my mailbox and it is over 500 MB. I have a user with over 4GB of mail.
    – BillThor
    Feb 13, 2011 at 16:51
  • 1
    depends how many users you have i guess. we have 150mb per user and the 75gb limit on exchange 2003 is a real nightmare.
    – Sirex
    Feb 13, 2011 at 20:31
  • @sirex: Time to upgrade if you run into that limit. All modern Exchange versions support 16TB databases. :)
    – pehrs
    Feb 13, 2011 at 21:18
  • 4
    @pehrs - it's not always that simple Feb 13, 2011 at 22:06
  • 1
    I do wish that it was :)
    – Sirex
    Feb 14, 2011 at 7:56

6 Answers 6


The best way to encourage users to take up a new service, is to make sure that it is better than what you currently provide, otherwise what's the point. I would make sure they have the ability to store more than 200mb, or are trained in how to prune their mailboxes of large attachments, although lets be honest, who really does this?

We moved away from Personal Folders some time last year, and despite the added few minutes a week I might have showing users how to clean their mailboxes up, I haven't looked back. It was definitely met with some scepticism at first, as most users had been used to a 500mb limit on their mailboxes and then archiving to .pst since long before I joined the company five years ago, but approaching it in gradual stages lessened the burden.

The first step was to increase the disk space on the Exchange server, costs of which were quickly justified to management by explaining the cost of lost data in a corrupt personal folder as well as the time taken to attempt to restore corrupt .pst files, they bought it pretty quickly.

The next step was to write some documentation for users on how to decrease the amount of data they stored in the mailboxes / personal folders, the best way to do this is to explain that it's not necessaries the amount of emails you have that take up the space, moreso the size of each email. I showed them that not all emails are the same size, and how they can free up 50% of data by cleaning up the largest 10% of their emails. I found that 70% of the users cleaned up their email after this

Finally, after explaining to the users the pitfalls of personal folders and the benefits of mailbox storage, such as automated nightly backups of their data which could be restored to a point in time if they were to lose anything, the ability to access their emails from anywhere they needed, as well as stating (with management approval) that we would no longer be supporting personal folders corruption, as a superior service was now available (I should add, that I never refuse to support an issue if it arises, but I've found that sometimes telling your users something is no longer supported is enough to encourage them to move to the new system) I migrated their personal folder data into their mailboxes as a goodwill gesture, over the course of a few weeks.

I then monitored the amount of data used by each mailbox for a few weeks and adjusted limits on a per user basis. Most remain with a 1gb limit, a small few require 2-3gb and quite a few others on 500mb. The reason I didn't set these limits prior to the migration is that I figured most users would delete a lot of older emails when they knew everyone else was doing it, which actually worked okay.


I have a lot of understanding for your users. You are doing a fundamental error of system administration: You create a solution that is easy for the sysadmins, but forget the needs and requirements of the users. 200mb per user is simply insane, and it is a limitation that causes problems for them, as they have to bother with archives and backups. This is wasted time and wasted money. The cost of 1gb of storage compared to the time it takes to sort 1gb of emails is extremely bad on the cost/benefit scale.

Why don't you provide your users with "unlimited" storage space? In practice, it won't grow very fast. It will take away the whole problem with the local archiving when the users no longer need to delete e-mails.

So, what you should be telling your users is "You don't need personal folders anymore. We will store all the e-mails for you, and take care of the backups."

  • 5
    Completely on the spot +1
    – lynxman
    Feb 13, 2011 at 11:57
  • 1
    +1. In IT projects where there has to be significant disruption to the users, the way to win them over is to understand what they do any why they do it, then ensure that whatever you change still leaves them a reasonable way to accomplish their tasks. In this case, unlimited mailbox size or some kind of automatic on-line archive fits that bill. Feb 13, 2011 at 19:14
  • 1
    +1. I've seen users in sensitive environments work around the limitations of a small inbox by keeping (unencrypted) copies of their mail on their laptops, even though they fully knew not to place sensitive information on their laptops.
    – Alex Holst
    Feb 13, 2011 at 21:41
  • 1
    This answer start of good and then takes a nose-dive straight into absurdity with the "provide your users with "unlimited" storage space". Have a -1 for not living in the real world. Feb 13, 2011 at 22:37
  • 1
    Not to mention, when you're talking about a system like Microsoft Exchange, where more messages in an inbox directly translates to more IOPS, which stresses what's already the biggest bottleneck on your server performance, giving users the ability to keep things around forever isn't on anyone's best-practices list. "Let the users have unlimited everything" is a great system when you're not operating at scale. Feb 14, 2011 at 19:35

It's really easy. Well it's easy to say and easy to understand. Might be difficult to do, however.

Simply put, you need to understand your users problems, and then you need to solve their problems, not the IT Department's problems. If they are using PST files then find out why and address that. If they are reluctant to change then find out why and address that.

I sympathise with the reasons why you can't just give people 'unlimited' space on the email server. But I sympathise more with people who are just trying to get their work done and have to cope with obstacles the IT department is (so it feels to them) placing in their way.

You might think "but we don't place obstacles in their way". I'm sure you don't intend to, but consider this: No-one in their right mind would want to use a PST file. I mean really, do you get up on Friday mornings and think "It's been a rough week. I think I'll turn the week around by treating myself to a new PST file!". At least I really hope you don't. So if your users are doing this then either ALL of them are crazy or they have problems which the IT department are not addressing.

Their reluctance to use the mimecast feature could be a lack of understanding how it works, it could be that it hasn't been properly explained to them from their point of view (as IT people we typically get focussed on how cool some piece of tech is and not on how it makes things easier for our customers) or it might be a trust issue - if the IT department has been unhelpful in the past over email space and the users have created PSTs out of desperation themselves then they may see the new system as a 'grab' to take control of their data away from them and put it back under a regime that has not always been sympathetic to their needs.


PST files get a bad wrap and sometimes it's overblown and unwarranted. If my company uses Microsoft Exchange server then using PST files is generally frowned upon. If my company uses an external email provider that supports only POP then there's almost no alternative to using PST files. It's not that PST files themselves are bad, it's the fact that users generally tend to let them grow to mammoth proportions and the fact that they're not easily managed from a system perspective. I agree with pehrs in that you're creating a system that works for the management without taking the needs of your users into account. You're proposing to take something away from your users without providing them a way to retain their emails once they've surpassed whatever mailbox size limit you choose to impose.

I see a lot of questions here that fall in to a pattern of "this is bad" or "I know I shouldn't do this" without the requisite analysis as to why "this is bad" or why "I shouldn't do this" in a particular scenario. The use of PST files is one of those subjects where there is a lot of "PST files are evil" hyperbole that is just so much jumping on the bandwagon without being given any critical thought as to how they apply to your specific situation. Are PST files really evil? Are they really such a bad thing? The answer is no. Can they be problematic? Yes. It's your job to analyze the risks and benefits of using them in your organization and determine whether or not using them is a workable solution, and if not, implementing an alternative that works for your users.

The IT staff, resources, and infrastructure is there to enable the business to be smarter, more efficient, more productive, and more profitable. You are there for them, not the other way around.


I am one of those users that uses Lotus Notes and have been restricted to 200MB.

  1. I know you're talking about Outlook and not Notes, but I need to vent and say that Lotus Notes is horrible (please never implement this); it's horrible to open, use, navigate, and script for. So this is more a precautionary statement, then addressing your question.

  2. 200MB is also stupid, especially when you get excel reports that are 3-10MB a piece, or someone wants to add unreduced images/signatures to their emails, or even the common HTML emails. Today the minimum should be 2GB per mailbox, but really somewhere between 5-10GB is suggested. Keep in mind though, people will always use/maximize what they're given. If you give them 10GB, they will eventually use that much and ask for more. On the flip side, 200MB is almost nothing, it's almost equivalent to 10MB, since they're deleting and making space every time they get new mail.

As for Outlook and pst issues, the pst file can be good. The .pst file is used for more than just local storage of emails, it also has:

  • Calendar appointments
  • To-do list info
  • Most importantly: Contacts

I think the local address book (contacts) information is the key thing that people might not want going to a cloud environment. Something you should consider is to synchronize your .pst file with your network profile so that it can be accessed from anywhere.

On the other hand, .pst files do have some bad things, they are:

  • often corrupted causing emails and other data to be loss
  • reach a critical size of their own (2GB for older ANSI, 20GB for Unicode), which increases the chances of corruption, or other problems with your system
  • are not very secure (it's easy to bypass any password measures)
  • newer versions (Outlook 2003 and on) are not backward compatible with older version of Outlook, which might be important if you have contingency sites, older desktops, or older laptops that run older version of the software

Here's a more complete list of all the bads.


The key stakeholders on the business side of the house need to understand why IT wants to banish PST files. The means folks in the trenches as well as the executive type people.

PSTs to the users aren't "bad" or "evil" -- they are an essential tool that allows them to get work done. Most folks aren't aware of the risks to the company in the event of litigation or the other negative things that keep IT people up at night. An archive accessible via Outlook should make end-users do backflips -- the fact that they aren't means that you need to work on communicating with them.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .