How to recover emails from oversized OST file
Access Data stored in an OST file, which has crossed its maximum size limit
Microsoft Outlook, world’s most preferred email client enables its users to work in an offline mode. Working in offline mode gives you the freedom to work with Outlook when your connection with Exchange Server is broken for a long time, you are away from Exchange Server, or Outlook is not able to connect with Exchange Server due to network issues. MS Outlook allows you to work in the offline mode in the same way, as you do in online mode. The only difference is the work done in offline mode is updated on Exchange Server when a connection is established to it.
When you select to work in offline mode, Offline Storage Table (.ost) file gets created on your computer system. Microsoft has set a size limit for this file, OST maximum size is 2GB in Outlook 2002 and earlier versions while the size limit has been extended to 20 GB in Outlook 2003 and later versions. At the time, .ost file crosses its size limit it becomes unusable i.e. the emails, contacts, and other data stored in it cannot be accessed sometimes the user may also come across situation like large Outlook OST file is not receiving email. At this moment, you may need to convert OST to PST or conduct OST file compress in Outlook to recover OST file data.
Once the .ost file has crossed its maximum size limit, Outlook’s coordination with Exchange Server comes to an end. In this situation the question on user mind is how to recover emails from OST file. Firstly, lets us take a view of the error messages thrown by Outlook. Some of the most common error messages that you may get after the .ost file has exceeded the maximum file size limit are:
“Errors have been detected in the file <file_path>. Quit all mail-enabled applications, and then use the Inbox Repair Tool.”
“Task 'Microsoft Exchange Server' reported error (0x00040820):'Errors in background synchronization. In most cases, further information is available in a synchronization log in the Deleted Items folder.”
How to know that .ost is approaching towards its maximum size limit
Now, when a user is asked what is stored in OST file, the important of its data cannot be ignored. Therefore, it is recommended to keep track of the size of .ost file so that you do not face problem in accessing data stored in it and need an OST to PST tool to convert OST to PST. A very quick and easiest way to confirm that .ost is approaching its maximum size limit is the pauses that you start getting as the size of .ost file is increasing. For example, if you need to wait for a long time than usual when sending/receiving emails, finding emails, etc. then you should understand that the OST maximum sizeis approaching towards its maximum size limit.
For the updated Outlook version the PST limitation is quite high, even though it can get prone to damage issues. Outlook 2010 OST file size limit is more than 20 GB but then to users can witness errors like ‘Outlook data file cannot be accessed’ OST file Outlook 2010 or the Outlook 2010 OST file cannot be accessed.
How to reduce the size of .ost file
When you start getting interruptions during send/receive operation, you should think about reducing the size of .ost file. User also prefers deleting emails when OST file size is exceeded, but it should be perform under proper guidance so that important data does not get deleted. To reduce the size of the .ost file, select File > Work Offline in MS Outlook. Now, delete some of the emails having large attachments and then compact the .ost file. Do not forget to compress the .ost file because until you do not compress the .ost file, its size will not be reduced.
What to do if .ost file has already crossed its maximum size limit
In case, the .ost file maximum size profile is crossed limit and you are getting above-mentioned error messages then the only way for you to access the data stored in .ost file is making OST to PST conversion. Download Kernel for OST to PST conversion tool to successfully convert OST to PST. Once the OST is converted into PST, you can open the PST with MS Outlook by selecting File > Open > Outlook Data File option. Kernel for OST supports MS Outlook 2010, 2007, 2003, 2002, 2000, 98, and 97.