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?

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

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/

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.

Hi,

I understand that there will be automatic compaction when the white space reaches around 20% of the data files size and the computer is idle.

Is there anyway we can track or find out when is the last sucessful automatic compaction?

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

• Edited by Paul wilson 963 16 minutes ago

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

• Edited by Paul wilson 963 Wednesday, April 29, 2015 7:12 AM