Access Violation crash

I'm having trouble adding IAP to my Unity 2018.3.7f1 Android project running on Windows 10. I enable IAP in the services window and then press Import which then runs the Unity IAP installer that reports that the IAP serivce is disabled even though it is clearly not, after which the editor goes on to crash. I tried many ways to fix this but nothing worked, I erased everything but the asset folder, ran the editor as administrator and tried adding IAP through the package manager first which also crashes the editor. The editor logs report one of these 2 similar errors:

Unity.exe caused an Access Violation (0xc0000005)
in module Unity.exe at 0033:42b660f7.

mono-2.0-bdwgc.dll caused an Access Violation (0xc0000005)
in module mono-2.0-bdwgc.dll at 0033:a33d56c5.

I tried importing the IAP package in a blank new project and it worked fine. I would appreciate any help in fixing this.

 

I might recommend reverting to the backup/prior source code version of the project just prior to the import if available, and/or follow the steps in the below link. It sounds like your import may not be properly seeing the UNITY_PURCHASING define, in case you have any editor scripts running or similar. https://forum.unity.com/threads/iap-troubleshooting-remove-and-reinstall-unity-iap.511747/