Frequently Asked Questions

error message "Class not registered" and "Cannot start Jet Engine"

Manual Installation for DAO350.dll file in 64-bit environment

In some cases of 64-bit Windows 7, 8, and 10 operating systems, the installation and registration of dao350.dll is blocked, either by anti-virus software or by Windows itself. BSI applications like Simian and WaveCart require the 3.5 version specifically for building an audio database as newer versions (3.60 / dao360.dll) are not backwards compatible. If you are receiving errors “class not registered” or “cannot start Jet Engine”, then you will need to manually register the DAO350.dll file.

Figure 1 - Common error messages due to missing or unregistered DAO350.dll

To manually install this component perform the following steps:

  • Verify the dao350.dll file is located in the following folder: C:\Program Files (x86)\Common Files\Microsoft Shared\DAO

(If the file is not present on your system, a copy can be downloaded from and then moved to that folder).

Figure 2 - Folder location of DAO350.DLL

  • After saving the file to the proper location, go to the Windows Start menu (left click in Windows 7 or right click on Windows 8.1 or click in the search box next to the Windows Start menu button in Windows 10) and use the Search feature to search for: cmd
  • The cmd.exe (a.k.a Command Prompt) application will be found.
  • Right click on the cmd.exe result and choose Run as administrator.
CMD searches in Windows 10, 8, 7
Figure 3 - Windows 10, 8 & 7 searches for Command Prompt "cmd" with right click menu option Run as administrator being selected

  • At the command prompt, type:
cd \windows\syswow64

  • Press the enter key. On the next line, enter the following:
regsvr32 "C:\Program Files (x86)\Common Files\Microsoft Shared\DAO\DAO350.DLL"

  • Then press the enter key

Figure 4 - Getting the correct syntax in the regsvr32 command is important. The word wrap is OK.

  • When all the steps are followed and entered correctly you will receive the RegSvr32 succeeded message.

Figure 5 - Success!

 Last updated Thu, Jul 10 2014 1:26pm

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