How to fix corrupt Outlook ost files
There are frequent questions about how to repair an .ost file mostly attributed to some unknown problems being encountered with the presumption is that the underlying source of the problem is the .ost file associated with the email account.
In a nutshell, the quickest and best way to fix any problems with an .ost file is to let Outlook recreate it. That’s accomplished by deleting the file. Actually renaming an .ost file would be the preferred approach so that you can revert back to it if necessary.
The one drawback to this approach is if this involves an extremely large email account which would result in a long time being required to rebuild the ost file. Another drawback would be that an internet connection is required which may not be available.
IMAP OST files – OL’2013/’2016
One thing that should always be done in reference to any ost file associated with an IMAP email account configured in OL’2013/’2016 is to ensure that you have all data backed up in any folder in the IMAP folder tree with the words “This Computer Only” in the folder description. This would be done by exporting the OST file to a PST file. Failure to do so will result in the loss of any data contained in “This Computer Only” folders since that data is not sync’d the server hosting the IMAP email account.
Using 3rd party tools
There are various 3rd party utilities available that claim to repair OST files or convert it to a PST file, most of which are expensive. Not all tools are created equally and not all utilities convert all ost files so be sure to test any such tool prior to making any purchase.
One of the most comprehensive and reliable tools I’ve tried is OST2 from 4Team which has both a free and paid version.
Offline recovery options
If the problem(s) being encountered are not preventing access to the OST file itself from within Outklook, then the first thing to try is to export the entire to a PST file. That would at least provide a permanent offline backup.
If an Outlook export doesn’t work, the suggestion would be to use the free version of the 4Team OST2 program to create a PST file. The free version requires that the OST file is configured in an active Outlook profile whereas the paid version enables conversion of an orphan ost file not associated with an email account.
Potential causes of problems
Should always be remembered that what appears to be an OST problem may in fact only be a symptom of another issue (the real cause). These causes could be the result of an issue at the server level or a corrupt Outlook profile. If an ost file is getting constantly getting corrupted then it would be important to look at what keeps causing the problem.
Category: Outlook - How To
