OST files are basically the files of MS Outlook which are stored in email servers which in turn helps you to work offline. As soon as you come in contact with internet it synchronizes automatically. Fullform of OST is Offline Storage Table.
PST files are basically the files which are stored by MS Outlook in your computer. Fullform of PST is Personal Storage Table.
So now let’s get into the reasons:
Reasons To Convert OST Files To PST
This type of issues occurs when there is an interruption during the synchronization process of .ost files with the email server. If this happens there is a great chance of your OST files getting corrupted.
Size limit is also a big issue in corrupting your data. If your files exceed the mentioned size then you might face corruption. For Example: OST files size limit in MS Outlook 2007 is 20GB and in Outlook 2010 & 2013 is 50GB. So always keep a check on the size of your files.
These are the two main reasons of corruption and to Convert OST file To PST
How To Do OST To PST Conversion
Exporting you .ost files to .pst files is a good way to convert your files. But the biggest issue with this step is that it only converts your content part of your email messages.
Keep in mind, archiving is not a process to convert OST files To PST. But it helps you in archiving your old data which in turn helps to keep a check on the file size.
Drag & Drop
Drag and drop method is one of the most simple method. Here you just have to create a new pst files and just drag and drop your OST files in it.
But the problem is it is a very time consuming method.