SAP Knowledge Base Article - Public

1218154 - Report data not updated immediately in RDC application connecting to Access


A Microsoft Visual Basic application uses the Report Designer Component (RDC) as the reporting development tool. The report connects to a Microsoft Access database.

When the database is updated, and the report in the application is immediately viewed, the database changes are not shown on the report. When running the report a second time, the database changes appear.


This behavior occurs because Access uses a write cache. The report cannot read the database changes that have not yet been finalized to the database file.

This can happen when there are multiple processes accessing the database file at the same time. One process may be reading the database while another is updating it.



For more information, go to and search for knowledge base article 111888.


The following registry key will ensure that Crystal Reports acts in a thread safe manner:


WARNING: The following resolution involves editing the registry. Using the Registry Editor incorrectly can cause serious problems that may require you to reinstall the Microsoft Windows operating system.

Use the Registry Editor at your own risk. It is strongly recommended that you make a backup copy of the registry files before you edit the registry. For information on how to edit the registry key, view the 'Changing Keys And Values' online Help topic in the Registry Editor (Regedit.exe).

Refer to Note 1323322  for more information.


- For Crystal Reports 9 -

1. Install the appropriate Hot Fix update as outlined in Note 1217210.

2. Using the Registry Editor, go to

HKEY_CURRENT_USER\Software\Crystal Decisions\9.0\Crystal Reports\Database\DAO

3. Set the value of the 'IsThreadSafe' key to "Yes".

- For Crystal Reports 10 -

1. Using the Registry Editor, go to

HKEY_CURRENT_USER\Software\Crystal Decisions\10.0\Crystal Reports\Database\DAO

2. Set the value of the 'IsThreadSafe' key to "Yes".


TIMING DATA THREADSAFE MULTITHREADING EXCLUSIVE MUTEX 9 RDC9 RDC10 c2014297 Report Designer Component Database performance Microsoft Access , c2016931 , KBA , BI-RA-CR , Crystal Reports designer or Business View Manager , Problem


SAP Crystal Reports 10.0