How to backup/recover Outlook ost data files
With the introduction of OL’2013 and the use of an OST file for IMAP accounts, many people are getting caught off-guard in the unexpected loss of contact/calendar information when the IMAP account gets deleted from the Outlook profile or not realizing that any OST file can only be opened by the Outlook profile/email account that was used to create it. In the case of .ost files associated with Exchange accounts, all data is stored on the server including contact/calendar data. IMAP accounts, on the other hand, store contact/calendar data in folders with the added description of “This Computer Only” which means the data is only stored locally. The IMAP protocol does not support contact/calendar data syncing.
What is a OST file?
An OST file is an offline data store (data file) the is a “mirror” of the information stored on the server the last time Outlook connected to the email account. If the .ost file for the account is not found by Outlook when it is opened, a new one will be created for it. Any time an account involving an OST file is configured, a new OST file will be created, you cannot set Outlook to use a pre-existing OST file. You cannot open an .ost file on its own. Orphaned .ost files (ones that you have copied thinking that it’s a backup). Orphaned OST files will require a 3rd party OST2PST conversion program.
About OST Conversion tools
There are a variety of products available from different vendors at varying price points.
Things to look for:
- Does it handle all OST file versions from all versions of Outlook (i.e. Outlook.com / Exchange / Imap)?
(most products from the major vendors involved with OST2PST conversion/recovery do) - If it’s important to you, is user-defined data converted?
(quick tests done just prior to this article being published using products from 3 of the major vendors – the answer is no) - If custom forms are being used – do contacts created using a custom form get properly converted?
(similar to tests run for just user-defined fields using a standard form – the answer is no
The majority of people would not be impacted by the custom form/user-defined field issue but for those who do use either simple user-defined fields or have published a custom form to a folder, this can be an unpleasant and unexpected surprise. In the case of orphaned OST files, any user-defined field/custom form data should be considered lost.
It should also be pointed out that if you simply used the Outlook export function to save data from an OST file to a PST file, the user-defined fields will be exported but any user-defined field info related to a contact item created using a custom form will not have any of that data saved in the PST file. A way to safeguard that info would be to use SafePSTBackup Enterprise which does retain all that data in the PST file created from an OST file but the ost file must still be accessible from the Outlook profile/email account used to originally create it.
In short – make sure that you conduct your due diligence for whatever program you might be planning to purchase <prior to any purchase> to make sure it does what you expect/want it to do.
Account types that utilize an OST data file
Ol’2013/’2016
- Outlook.com/Exchange (each will have self-contained contact/calendar folders that sync with the server)
- IMAP (contact/calendar folders will have the added designation of “This Computer Only”)
OL’2010 and earlier
- Migrated Outlook.com accounts using the Exchange protocol
- Exchange
- Outlook.com accounts still using the Outlook Hotmail Connector (contact/calendar folders are self-contained and will sync with the server using the MAPI delta-sync protocol)
Very important items to keep in mind for OL’2013/’2016 IMAP Accounts
If the IMAP account is the first email account configured for the profile, the contact/calendar folders in the IMAP .ost file will be the default contact/calendar folders for the profile regardless of the other Exchange/Exchange ActiveSync accounts have also been configured. If the IMAP account gets deleted, as stated, the data in the folders marked with “This Computer Only” will be lost.
There is no way to access any .ost file (from any account type) from within Outlook (any version) once it has been separated from the original Outlook profile/email account that created it.
If an IMAP account is NOT the first email account configured in the profile, it will not contain contact/calendar folders. Instead, the default contact/calendar folders will be contained in the default Outlook data file shown under the <Data Files> tab in <Account Settings>
How to backup OST data files
- Manually export the complete ost file to a pst file via Outlook’s “export to PST” function with limitations as noted above)
- Use a 3rd party OST2PST conversion program (with limitations as noted above)
- Use a 3rd party program like the enterprise version of 4Team’s SafePSTBackup program which will create a PST file backup of any OST file
Why <backup> an .ost file?
As mentioned, an OST file is a mirror of what is contained on the server (IMAP contact/calendar folder excepted) so all the data will be recreated whenever a new ost file is created and Outlook connects to the account. The primary reason for making a backup an OST file would be in the event there is concern that you would no longer have access to the email account applicable to a given OST file. Making on-going or daily backups for these files is otherwise questionable at best.
How to safeguard OL’2013/’2016 IMAP Contact/Calendar data
Essentially there are three approaches that can be taken
- Export the contact/calendar folders to a PST file on a regular basis – a tedious approach which most people are likely to forget to do and would not be a viable approach for those using custom forms
- Use SafePSTBackup Enterprise and set it to make scheduled backups of the OST file (user-defined fields and custom form data is retained)
- If there is no other default data file and more importantly, the default data file is not an OST file associated with an IMAP account, create a new PST file in the profile and set this PST file as the default for the profile. Once done, contact/calendar data should be moved to the applicable folders in that PST file after which the PST file can be copied (backed up) just like any other PST file associated with the profile.
- Creating a new PST file is done by:
a) click on the <Home> tab
b) click on <New Items>
c) select <More Items>
d) select <Outlook Data File> and create the file in the location of your choice - Setting the newly created PST file as the default data file is done by
a) Go to <File>
b) Account Settings
c) Data File tab
d) Select the pst file and set it to be the default
You can also reference this post for additional information How to Protect Outlook ‘2013/’2016 Imap Contact/Calendar Data
Recovering versus converting an OST file
There can be times when problems arise in the content of an OST file. Unless this is an orphaned file no longer associated with an email account, the best approach would generally be to let Outlook recreate the .ost file and re-sync the data. If the problem persists, the cause of the issue is very likely to be something contained on the server so repeatedly running an ost recovery program similar to ScanPST would serve little purpose. Generally, most OST2PST conversion programs from the leading vendors scan an OST file when opened prior to saving the file as a PST file.
Category: Outlook - How To
