There can be multitude number of reasons why a model does not open in AutoPIPE. Select link that closely resembles information from AutoPIPE Log file, Event Viewer, etc..
Note: see link here for general options available to fix the model
Open AutoPIPE's Log file and review the last lines of the file:
Open computer's Event Viewer, select Windows Log> Application> find recent Error event, select it> and review the General details about it:
Faulting application name: autopipe.exe,
Faulting module name: ucrtbase.dll
Exception code: 0xc0000409
Bentley AutoPIPE has crashed