Plugin Error – Security accessibility of the overriding method must match the security accessibility of the method being overridden – Quick Fix

Hi Folks,

I recently came across the above error for one of my Dynamics 365 Plugins…this blog talks about applying a quick fix.

While debugging our Plugin logic line by line to understand why it’s not working, observed this error for messages like RetrieveMultiple, Retrieve when I use any Organization Service call.

This was a .Net version downgrade issue caused by ILMerge as I downgraded one of the DLL to 4.6.2 version from 4.7.1. If you see this issue even without downgrading your DLL, you can use this fix.

After some research I came across this article and applied the same to my assembly which fixed the issue. Added these lines to my AssemblyInfo.cs class file..

[assembly: AllowPartiallyTrustedCallers]
[assembly: SecurityRules(SecurityRuleSet.Level1)]

Hope this helps someone who is facing the same issue down the line in their Plugin Development, Debugging…

Thank you for reading…

Cheers,

PMDY