What to do with 
- Issues with Large OST Files
- In case of OST File Corruption
- Problems with OST Orphaned
Dealing with an Oversized Outlook OST File
MS Outlook 2002 version and all other lower versions have the size limitation for the offline folders file, the OST file to up to only as large as 2GB size. When the OST file reaches this threshold limit or exceeds it, then user is bound to encounter some error messages, like as follows:
- Cannot add any new data to the OST file
- Cannot synchronize the OST file with the Exchange server
- Cannot open or load the OST file at all
Outlook program and MS Exchange server application usually do not have any built-in features or functions for rescuing the user from such problems of oversized OST. Thus only OST to PST conversion is suitable way that helps to deal with an oversized Outlook OST file.
Errors often seen at OST Corruption Time
- Outlook ost file is not an offline folder or MS Outlook unable to open xyz.ost file.
- 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.’
- Can’t copy the item.
- Errors have been detected in the file xxxx.ost. Quit all mail-enabled applications, and then use the Inbox Repair Tool.
- Errors in background synchronization. In most cases, more information is available in a synchronization log in the Deleted Items folder.
How to Open Orphaned OST File?
If user is connected with Exchange server and wants to open an orphaned OST file then few manual steps will help to do so:
- Create a new user profile with same MAPI setting (same MAPI details is required)
- Now open Orphaned OST file with newly created profile
- Once OST file will open you can export it into Outlook PST format through Import Export Wizard
Use An External Solution to Fix OST File in All Cases:
As discussed above in detail, you can make out very much that Microsoft does not offer any satisfactory method to solve the over-sizing OST file issue or to re-connect an Orphaned OST file. In light of this absence, the best solution that rests in the hands of a user is to try out an easy to use OST Recovery solution (PCVITA OST Converter) in case he does not know what to do if Outlook OST file does not work.