Helping people with computers... one answer at a time.
Outlook maintains a database of your email in a file called a PST. If that file has not been properly closed it'll be checked for errors on startup.
Every time I open Outlook it tells me that it was not closed properly and the data file is being checked for errors. How do I correct this issue?
Outlook's funny that way.
I would run into this issue from time to time when using Outlook myself. What I found was something that most might find surprising...
Exiting Outlook didn't always exit Outlook.
Like many programs, I think Outlook tries to optimize for what its designers consider the most common usage scenarios. In this case, what that means is that sometimes after exiting Outlook, I would find it was still running, though not open or on my desktop. I'm not sure if that was intended to speed it up the next time I opened it (which it did) or what, but that's what I saw.
The difference was actually even more obscure:
If I closed Outlook by typing ALT+F4 (the Windows standard 'close application' command), Outlook would disappear from my screen, but would remain running behind the scenes. Depending on the version of Outlook the Outlook icon would remain in the notification area.
If I closed Outlook by clicking on File and then Exit, Outlook would actually exit completely.
The reason that this might relate to your situation is that when Outlook remains running, it does not close the PST file. That, in turn, means that if Outlook is forced to close immediately, say by a system shutdown, or particularly by turning off the system without having exited Windows first, the PST will be in that "not closed properly" state.
So, what should you do?
Here's my suggestion:
Try exiting using File->Exit and see if that makes a difference.
Always make sure that your turn your computer off by clicking the Start menu, and then Turn of Computer. (Yes, I know, clicking Start to Stop seems counter-intuitive, but the fact is turning off your computer is a process where a number of things need to be "cleaned up" first. Think of it as Starting that shut down process.)
Many of the PDA/cellphone syncing programs will actually cause Outlook to continue running, since they use Outlook to access your contacts and other information for synchronizing to your handheld device. If you run such software, you might consider turning it off and seeing if that gets rid of the problem.
If you continue to have this problem, just before you turn off your computer, run Process Explorer and see if Outlook is still running. If it is, then that is, at least, a possible indicator that what I'm describing here might be the problem. (You can terminate the process, of course, but that will almost guarantee that you'll get the "not closed properly" error, since that will prevent Outlook from closing properly.)
It's possible that Outlook is having an error on its own shut down and not reporting it. Check your anti-malware software to see if it's trying to interfere with Outlook - things like real time email checking can sometimes cause these kinds of problems, though typically more visibly.
You might consider a re-install of Microsoft Office, and making sure that Office itself is up-to-date with it's latest patches.
And finally, for completeness, I also have to encourage you to double check your anti-virus and anti-spyware software, making sure that both are up to date and have up to date databases. While it's unlikely that malware is the cause, it remains a possibility since malware does often like to mess with email programs, and Outlook is a big, popular target.
It all boils down to making sure that Outlook has the opportunity to completely and correctly shut down prior to turning off your computer. If that's interrupted or prevented for some reason then the error you're getting will result the next time you start Outlook.
Oh, and of course, making sure that some other program isn't stepping on your PST file for some reason. That's rare, and typically much more disastrous, but worth a look if the steps above don't resolve the issue.