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Delphi Troubleshooting

File not found: CDO_TLB.dcu


When compiling a Delphi unit, a "uses" clause generates the following error:

[Fatal Error] File not found: 'CDO_TLB.dcu'


The unit CDO_TLB provides access the the classes found in the library cdosys.dll, this provides access to various CDO (collaboration data objects) classes.

This error is generated if the library file cdosys.dll has not been imported into a unit.


Import "CDO". Do this by:

  1. Start up Delphi.
  2. On the "Project" menu in the main toolbar select "Import Type Library..."
  3. Scroll down the list and select "CDO". (If this isn't shown in the list then click [Add] and add "C:\WINDOWS\system32\cdosys.dll", then try again.)
  4. The "Class names" should then list "TMessage", "TConfiguration" and "TDropDirectory".
  5. Click [Create Unit]

These notes are believed to be correct for Delphi 6 and Delphi 7, and may apply to other versions as well.

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