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Question
Thursday, April 11, 2013 7:01 AM
Hi,
My mailbox about 3GB, but the OST file size seems 38GB.
After recreate new OST, it grow very fast back to very huge file size.
Any idea of this?
All replies (6)
Thursday, April 11, 2013 7:17 AM
Do you perhaps have a large amount of Public Folder Favorites or access to shared mailboxes?
If you have configured Cached Exchange Mode (CEM) to also cache these, then it can indeed add up quickly.
You can modify your CEM to no longer cache these or apply sync filters to reduce the size of the ost-file.
See: Reduce ost file size with Synchronization Filters
Robert Sparnaaij [MVP-Outlook]
Outlook guides and more: HowTo-Outlook.com
Outlook Quick Tips: MSOutlook.info
Thursday, April 11, 2013 7:17 AM
Its a common issue there can be a case when you have whitespace in your .OST and you need to compress it manually.
Check Here to Compact File Size:http://office.microsoft.com/en-001/outlook-help/reduce-the-size-of-outlook-data-files-HA010117945.aspx#BM3
Other cases can also affect the offline folder size, Check:http://kurtsh.com/2012/06/17/info-why-the-heck-is-my-outlook-ost-so-big/
Thursday, April 11, 2013 7:27 AM
Hi,
The CEM is configured with Download shared folders but not Download Public Folder Favorites.
The calendar will not available if uncheck download share folders?
It is growth too fast and the indexing get halt because the OST too big.
Thursday, April 11, 2013 7:41 AM
Hi,
I understand that there will be automatic compaction when the “white space” reaches around 20% of the data file’s size and the computer is idle.
Is there anyway we can track or find out when is the last sucessful automatic compaction?
Wednesday, April 29, 2015 6:26 AM
Hii,
MS Outlook File grows as you create and receive items. Sometimes user of MS outlook encounter an error that OST file exceeded its default maximum file size while sending and receiving emails. Deleting some data item from OST file might not decrease the file size in proportion to the data that you deleted.
To reduce the size of ost file you can either use Synchronization Filter method or you can compact the size of ost file on advanced tab settings of exchange account. Synchronization filter Method restricts particular data items to be synchronized from exchange mailbox to ost thereby reducing the size of ost file at some extent.
Steps to be followed for Synchronization filter method,
- Right click on folder and click properties
- Click synchronization tab and then click Filter
- Now provide the appropriate criteria for filtering that you want according to what data items should arrive in folder.
- Click Ok and open outlook now
follow this thread foe more information:https://social.technet.microsoft.com/Forums/office/en-US/463dbd67-81e6-4785-b377-cb9df404c635/large-ost-files-on-outlook-2010?forum=outlook
Thursday, September 6, 2018 9:24 AM
Hi Exchange2010,
OST file contains entire mailbox data which has been gathering since your user account has been created. From then, none of the data has been deleted and OST files have become oversized creating an error “ OST file too large”. The large sized OST file contains the components such as:
- Hidden items.
- Mailbox items like emails, contacts, journals, events, to-do lists etc.
- Favourites.
- Shared folders associated with an additional mailbox or Exchange account
This issue can be fixed by using various manual and automated methods-
1- Compacting mailbox data by reducing OST file size
2- Disabling all add-ins.
3- Auto archiving method.
4- Using an OST to PST converter for converting OST to PST file format as OST can further be corrupted. So. it is better to convert OST to PST.
Hope it helps.
