Ost format file cannot be accessed.

[RenRen]

Hello everyone,

I have created .ost file in Outlook 2013 and after saving, I tried to open the file and got an error, The file cannot be accessed.

So my question is, how to view .ost format file?

[stiltman]

OST is a cache file that syncs outlook with the mail server. It is created when you setup your account in Outlook.
PST is an Outlook data file that you can create 1 to many of. That file can be opened in Outlook under a different account (assuming no password protection)

You can export your email account (OST) to a PST in Outlook under import/export options

[RenRen]

Thanks for useful information

[Nelson37]

The selection of utilities to handle OST files is extremely limited as compared to PST files. Few if any free ones. Alternative download methods may be required.

I would agree that a suggestion to use Outlook to export a file that Outlook cannot open is not very useful.

[aedipuss]

LOL if the program that created the file can't open it, you're out of luck. the only thing that file is good for is deleting.

[Nelson37]

This is an Outlook database file. Use of external programs on such files to do repairs or extractions that Outlook cannot handle is frequently mandatory. Your reply is non-sensical.

Now, if this is a brand-new, nearly-empty file as possibly indicated, then yes, simply delete and re-create. However, in most cases that is just not a viable option.

[stiltman]

My OST is 19Gb. It's Outlook's cache file to my mailbox on an exchange server. I can delete my OST file and it will recreate itself, because all the emails are still on the Exchange server.

PST files are Outlook's data files, that in the old days were created at the same time you created your email account in Outlook. This is not the case since Office 365 came out
PST files, are mostly shown as "Personal Folders" or "Archive" in Outlook and are usually stored locally to C:\Users\username\AppData\Local\Microsoft\Outlook\ filename.pst
You can usually repair PST files using scanpst.exe. The only way to repair an OST is let Outlook do it on startup or delete it and let Outlook recreate it.

BTW, all this relies on Outlook using an Exchange server (or exchange server emulator) and Doesn't apply to Outlook using a POP3 account

[Nelson37]

There are numerous OST file utilities, to handle a variety of tasks, and there are a multitude of reasons to use them. Recovery of deleted records, emails from corrupted accounts, access to backup copies for deleted accounts, are just a few I have run into within the last year. In-house exchange server crashing with improper backups is another I've seen a long time ago.

The files can become corrupt, server data can be incorrect, accounts can be deleted, humans do strange things. Databases require tools, having only one is not a good idea.

[MdosS]

Here you can open ost file https://www.viewertool.com/ostviewer.html

[RenRen]

I want to say thank you for taking the time to share how to go about fixing this.

[Baldrick]

OST Viewer Tool can open ost file

I smell a spammer.