Delphi / Object Pascal · Exception

EClassNotFound Exception

What does EClassNotFound Exception mean in Delphi / Object Pascal?

A descendant of EFilerError raised when a DFM/stream references a component class that isn't registered or linked into the application - commonly a form using a third-party or custom component whose unit was removed from the uses clause, or a package that wasn't loaded.

EClassNotFound ExceptionDelphi (VCL) · Delphi (FireMonkey)

Condition

A descendant of EFilerError raised when a DFM/stream references a component class that isn't registered or linked into the application - commonly a form using a third-party or custom component whose unit was removed from the uses clause, or a package that wasn't loaded.

Fix

Make sure every component class referenced in the DFM has its unit in the project's uses clause, or is registered via RegisterClass at runtime for dynamically-loaded forms, and confirm any required design-time/runtime packages are actually deployed.

Related exception