We need an easy way to transform . OST in . PST ? What is the easiest way to do this? I just need to work with e-mail now, and I don't have such an opportunity…

I can offer you a great solution to your problem, take advantage of pst recovery online ---- https://outlook.recoverytoolbox.com/online/

Bitacube OST to PST Converter is another proficient application which provides few simple steps to convert OST to PST.
1) Add OST file
2) Preview OST file
3) Select destination (PST, Live Exchange, Office 365, EML, MSG, HTML)
4) Convert OST to PST

More information http://www.bitacube.com/ost-to-pst-converter.html

There are two possible ways to transfer the OST to PST one is the Manual or another is third-party software. But if we talk about the third-party solution then I also recommend the A2Z Migrations for OST to PST tool. It is the best option to convert the bulk OST file data to Outlook PST or other multiple formats at once. While you choose this OST to PST recovery tool you don’t have to pay the extra charges like $49, $149, or $299, you just buy the full version license at only $10.14 per mailbox.
For getting complete information visit: http://www.a2zmigrations.com/ost-to-pst-converter/

Try an application MailsSoftware OST to PST Converter to convert OST mailbox data to PST. It repairs the damaged and corrupted OST data by fixing the bugs in a single click. It provides an option for the user to divide the larger OST files to smaller PSTs with the same text-formatting structure and without losing any data attachments. Please visit the site to get more info: http://www.loopdesk.com/article/35033/convert-ost-data-to-outlook-pst-format

To know how to convert OST to PST, one can make use of a trial version of OST to PST Converter tool. Using a trial version, you will be able to know step by step process of OST to PST conversion. Once you get to agree with a free trial version, then I would suggest you to go with a full version of this tool. With the help of the full version, one can import accessible and inaccessible OST to PST, EML, MSG, Office 365, and Live Exchange Server.

Get More Info: http://www.edbmailrecovery.com/

I would like to recommend OST to PST Converter Free to transfer exported OST mailboxes to Outlook format. It is the latest tool comparing to the above software because it doesn’t necessitate the extraction of OST files so you can straight convert OST exported OST files to Outlook PST format. To know more info: https://www.softknoll.com/ost-to-pst-converter/