When you upgrade your Axapta 3.0 SP1-3 to the latest Service Pack 4, make sure you import the Hotfix HF30SP4_011 first.
If you do not install it, the upgrade may run for an extremely long time (but: no data will be harmed).
You can get the hotfix from Partnerguide or your Axapta partner.
Development tutorial: SysExtension framework in factory methods where the constructor requires one or more arguments
vor 1 Woche