Outlook is among the most famous applications used on Windows computers across the globe. Most of the official emails as well as personal emails are read on Outlook most of the times. There is a huge crowd that prefers synchronizing all of their mailboxes on Outlook. The personal folder file on your Outlook contains all of your emails that are sent or received by you. This has an extension of .pst and is called Personal Storage Table. There are other files which are called pst archive and ost files which contain information. Most users misunderstand these files which may be bad at times. Let us find the difference between pst file, pst archive and ost files on your Outlook.
If you browse through the system folders on your computer, you may find so many of pst and ost files from Outlook data. Their names might be different as per the situation when the file is saved, but the extension will be the same. A large amount of data is stored on the computer with these pst and ost files. if you do not know the difference between these files, you may end up corrupting important pst, ost files or deleting them. So in order to manage your data from Outlook, you have to keep a knowledge of pst, pst archive and ost files.
PST and OST Files
The fundamental difference between the pst files and the ost files is their tangibility. It means the pst files contain the actual data from all the emails from your Outlook mailbox. Whereas, the ost files contain cached files to be used in cached storage for your emails. The ost file on your computer memory is just the local copy or the cached copy of your Outlook data. The master copy of Outlook data is stored in the Outlook server and a local cached copy of the data is created in your computer memory which is called the ost file.
If you are using the previous versions of Outlook such as Outlook 2010 or Outlook 2007 on your computer, the cached content of your IMAP account is created in pst file. However, Outlook changed this in later versions of the application. Now your IMAP accounts in 2013, 2016 and the latest 2019 are created and cached in ost files.
There are some files and folder in the ost file which do not sync to the Outlook mail server and reside completely on your computer. Such kind of folders is marked as ‘This computer only’. This indicates that those files are totally in your computer memory have no chance to synchronize with the server. In some situations, your Outlook might also fail to sync the OST with the server. You need to be very careful while creating any backup file to keep the data safe. An old or corrupt file can give you error messages related to not opening of ost files. With the use of appropriate tool ost file cannot be accessed issue can be fixed. But this takes more efforts than creating a backup file.
The pst files on Outlook are all the same as each other. All the pst files store the Outlook email data in the same manner. You can access these pst files from another computer using Outlook. There is a very small but significant difference between pst files and pst archives.
If the pst files are not associated with any live email account on the computer, such as POP3 or IMAP, they are called pst-archives. You can also archive your Outlook data by creating a pst file and moving important emails to it. There is also an auto archive feature that you can use to make it automatically. In order to do this, you can set the parameters for archiving such as date/ freshness etc. related to the mail.
If you are using Outlook 2007 or previous versions:
Go to File > Data file management
For Outlook 2010 and outlook 2013:
Go to File > Account settings > Data files
The only way to archive the OST folder is by converting it to PST using a tool to change the OST to PST.
You can create or disconnect any pst file from the Outlook mail server to make it a pst-archive file. however, once archived, this data will not sync with the server anytime. This data will reside on the memory of your computer for transferring or keeping it as an archive of your emails.