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How to customize the OST synchronisation behaviour in PST Enterprise

  • Type: Knowledgebase
  • Date changed: one year ago
Solution #00007536


PST Enterprise, v3.1 or later


If the ?Wait for OST sync? setting is enabled in the Client Configuration, after each PST file is processed the PST Enterprise Client will perform a comparison of the data in the OST with the data in the mailbox to determine if the OST is synchronized. The PST Enterprise Client will not continue processing until the synchronization is completed or has timed out. By default, the PST Enterprise Client will check 200 times with a 2 second delay between each check. Every 5 checks, the current total count in the mailbox is compared with the OST. For synchronization to be considered complete, this must be at least 90% of the total expected count in the mailbox (i.e. the majority of data has synchronized to Exchange). The total duration (200 iterations with 2 second delay between each) permitted is 400 seconds, after which processing will proceed regardless of the OST synchronization status. This ensures processing isn?t blocked indefinitely.

If you have slow OST synchronization in your environment (e.g. due to limited bandwidth on slow links), you can customize these values if you wish to ensure all data in the OST is synchronized to Exchange. This may reduce throughput as the PST Enterprise Client will not be permitted to continue processing until the OST data is synchronized as per your defined values.

To customize the OST synchronization behavior:

1.       On the PST Enterprise server, browse to the installation directory, by default C:\Program Files (x86)\Barracuda\PSTEnterprise\Web.

2.       Take a backup copy of the web.config file (should you need to revert any changes).

3.       Open the web.config in Notepad.

4.       Locate the Application settings section at the end of the file, which starts with the lines:



5.       To adjust the delay in seconds between each check for OST synchronization (default is 2), edit the value for OstSyncDelay:

<setting name="OstSyncDelay" serializeAs="String">


6.       To adjust the number of checks for OST synchronization (default is 200), edit the value for MaxOstSyncIterations:

<setting name="MaxOstSyncIterations" serializeAs="String">


7.       To adjust the percentage difference between the mailbox and the OST which defines the threshold at which the synchronization is considered completed (default is ?90?, ?100? would be an absolute match), edit the 
value for OstSyncThreshold:

<setting name="OstSyncThreshold" serializeAs="String">


8.       Save the changes and close the file.

9.       The next time the PST Enterprise Client runs it will use the new configuration.