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.pst files are Microsoft Outlook's email and data storage containers. They can occasionally be damaged, but Microsoft Office includes a repair tool.

I am running Windows 7 and my Outlook has stopped working. It states that the folder that the .pst is in is damaged. I was hoping that you could provide me with a fix please and thanks. Error Message: Cannot start MS Outlook. Cannot open the Outlook window. The set of Folders cannot be opened. Errors have been detected in the file C:\Users\Avery\AppData\Local\Microsoft\Outlook\Outlook.pst

".pst" files are the container files used by Microsoft Office's Outlook email program to store all of your data. (Note that this is not Outlook Express, which is a different, unrelated program that I recommend that people stop using.)

When that file becomes corrupt for whatever reason, the potential for data loss is high. Fortunately, it doesn't happen often and being a single file makes it almost trivial to backup regularly.

But because it can happen, Microsoft includes a tool with Office to help repair your Outlook .pst file: scanpst.

Before you start

Before you run scanpst, you'll need to close Outlook if you have it running. Scanpst can't do its job if Outlook has the .pst file open at the same time.

After closing Outlook, I recommend making a backup of the .pst file. Because it's a single file, just copy it somewhere for safe keeping in case scanpst makes things worse or causes unexpected data loss (it's been known to happen.)

Locating scanpst

Scanpst, as its name implies, scans your .pst files for errors and repairs them if it can.

Even though you probably won't find it on any Start menu, scanpst should be included with your installation of Microsoft Office:

ScanPst.exe in the Microsoft Office 2010 installation

Here you can see ScanPst.exe in Windows Explorer where it's located in "C:\Program Files (x86)\Microsoft Office\Office14".

"Program Files (x86)" may be simply be "Program Files", depending on your version of Windows, and "Office14" may be some other number depending on your version of Microsoft Office (this example uses Office 2010 in Windows 7 64-bit).

Running scanpst

Double-click scanpst to run it.

Scanpst's interface is very simple:

Scanpst's interface

It only asks you for the location of the .pst file that you want to scan.

In your case, the error message told you exactly where to look: "C:\Users\Avery\AppData\Local\Microsoft\Outlook\Outlook.pst" and that's exactly what you would enter, or you could use the Browse button to locate the file.

In my example, my pst file is at "C:\Users\LeoN\Documents\Outlook Files\Outlook.pst".

After you've entered the .pst file location, click Start.

Scanpst results

If your .pst file is large, scanpst will take a while to perform its checks. If it finds any anomalies, it will prompt you before repairing them:

Scanpst reporting results

Even though you made a backup of the .pst file before we began, it's a good idea to let scanpst make another. You can never really have too many backups.

Click Repair and let scanpst do its thing.

After running scanpst

Assuming that all succeeds, you can now re-open Outlook and hopefully the errors will have been resolved.

If not or if you're at all curious, you'll also find a ".log" file in the same folder as your ".pst" file that may give you some clues as to what might be happening. Chances are that there will be a lot of technical gibberish, as .pst files are very complex, but as I said, perhaps there will be a useful clue.

Things to note

One of the most common causes of .pst corruption, and unfortunately data loss, is having an "old format" .pst (pre-Outlook 2003) that exceeds two gigabytes in size. Even though you may have upgraded Outlook itself, the file format may not have been automatically converted to a newer format capable of handing larger file sizes. If that happens to you, you'll need to upgrade the file format yourself.

In general, large .pst files are something to be avoided for a number of reasons. I do have a few hints for dealing with large pst files.

Unfortunately PST repair topics tend to be magnets for comment spam relating to third party tools that supposedly repair PSTs. As a result I'll have to reject any comment that looks like that kind of comment spam. If you're legitimately sharing a good experience - I apologize, please blame all the spammers - if you have a product you wish to promote, you can read up on advertising on Ask Leo!.

Article C4942 - September 30, 2011 « »

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Leo Leo A. Notenboom has been playing with computers since he was required to take a programming class in 1976. An 18 year career as a programmer at Microsoft soon followed. After "retiring" in 2001, Leo started Ask Leo! in 2003 as a place for answers to common computer and technical questions. More about Leo.

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Recent Comments
18 Comments
anton
August 8, 2012 8:11 PM

thanks a heap - a really handy tip

Marty W
August 17, 2012 10:09 AM

Leo: When running ScanPST.exe to repair a PST file, you should run the program 3 times in a row on the same file, or until it reports no more errors have been found. Even if it still shows errors, the program limits you to 3 runs on the file in one session.

Sarah Smith
November 22, 2012 12:41 AM

For applying pst file repair steps correctly through scanpst, it is necessary to identify the version of Outlook. These steps may differ from one version to another. You have stated good information about scanpst. Thanks for that !!. However, I have to say that we should not forget that this utility does not always solve the purpose of repairing the file. Thus keeping the backup is a safe option.

Regards
Sarah

Yuhannes Watts
December 1, 2012 10:28 PM

Leo - many thx for this post, it got right to the point and helped me find the the inbox function in the correct folder.

Tony
February 27, 2013 6:54 PM

Thank you Leo. Even though I don't know much about computers your instructions were right on.
Again thank you very much.