Notes about the DCU file extension:
Incorrect file associations could be the result of underlying issues within your PC system. As such it is highly recommended to scan your PC for invalid registry entries
, unused processes and other unfavourable system settings to identify slowdown issues.
The DCU file type is primarily associated with 'Delphi' by Borland Software Corporation. The format of these files generally changes from one version of Delphi to another so it's often not possible to use a unit compiled with a lower-numbered version of Delphi with a more current version.