You should use AllExceptions whenever you want to handle general exceptions that cannot be classified as Database, Security, Licensing or User exceptions, or you want to handle all exceptions in the same way.
You should use AllExceptions for the following exceptions:
An exception raised by the InboundSMSGetDetails System action;
An exception raised by an action of a system event;
An exception raised when importing data from MS-Excel;
An exception raised by an Extension or Methods of Web Services;
An exception raised when setting the locale for the current session, in the SetCurrentLocale System action;
An exception raised when using the TenantCreate System Action with an invalid Tenant name.
Any other exception that is not handled by a specific Error Handler. For example, when there is an error due to a division by zero, the only way to handle it is through AllExceptions.
In the eSpace you cannot handle just a specific exception for the Extension or the method of the consumed Web Service. However, if you need to identify the exception, you can use a session variable called ExceptionMessage. The value of this variable is not controlled by the OutSystems Platform; it contains the information provided by the SOAP protocol.
AllExceptions is the most general exception and you should have, at least, one Error Handler that handles it in your screen flow, in order to provide a more user-friendly error message to the end-user. Learn more about handling exceptions.
Handling All Exceptions
To handle a User Exception, simply place an Error Handler in your action flow or screen flow, and set its Exception property to All Exceptions.
If your Error Handler is in the screen flow, you should set the Abort Transaction and Log Error properties to Yes, otherwise Service Studio displays a warning message. Learn more about how does the OutSystems Platform handles transactions in exceptions, and how exceptions are logged.
Handle Exceptions | Exception Flow