Good day. I came to the inbox attachment in a letter format ost. my Windows (I have version 7) than any standard can not open. Downloaded resource Internet  utility that was supposed to help, but when opening the file fails. Please tell me what my problem is and how can I fix it?

Well a .ost file is an Outlook file used to store the offline copy of a mailbox when using an Exchange mailbox (or an IMAP mailbox I think), so it's not any kind of document and isn't something you'd normally expect to be emailed.

The actual details within the .ost file are specific to the email profile configured on the machine it was taken from, so you can't even attach it to Outlook (unlike a .pst file). There are tools out there for converting a .ost file to a .pst file so it can be read, but I haven't used any so can't confirm how well they work or what the cost of them is, but there's definitely no native way to open that attachment.

I'd suggest checking with the sender that they didn't accidentally save the attachment with the wrong extension, or if they really are intending to send you a copy of a mailbox, get them to export it to .pst and send you that instead, since that will be a LOT less work than trying to open that file.

• Marked as answer by Steve FanMicrosoft contingent staff, Moderator Thursday, March 06, 2014 2:48 PM

Hi samullandon,

OST file is created by MS Outlook on Exchange Server, on off-line Exchange Server all emails are store in .OST file but can not open by default. Use OST Recovery tool to easily open OST file into PST file format on off-line mode.

Get more info on: http://www.en.osttopstfile.co.uk/

There will be totally different solutions for gap OST files to Pacific Time format however choosing the one with advantages is often counseled.

You can find this helpful blog: 

http://software-imperial-ost-to-pst-converter.software.informer.com/

___________

USA|Digital|Forensic|LAB|

Manual guide to Convert OST file to PST file, which you can access pst file with Outlook email client to get your emails.

http://exchangeserverstips.wordpress.com/2014/05/22/step-by-step-guide-to-convert-ost-file-to-pst-file-manually/

Thanks

OST to PST Software is very effective restorer and convert corrupt OST files and save in PST format.

Read more information visit :

http://www.en.ostrecovery.org or http://www.osttopstconvert.recoveryfiles.org/

Here is an another utility to convert OST file to PST format known as OST to PST Converter software which is capable to recover email messages, complete attachments, appointments, contacts,journals etc and safely convert into PST file format. For more information visit here : http://www.pcrecoveryutility.com/ost-to-pst-converter.html