Attempted To Read Or Write Protected Memory Error

I create and delete a conditional formatting rule programmatically. The issue I am facing is when I try to delete the conditional formatting rule that I programmatically created, I ran into the following errors:

1. Exception from HRESULT: 0x800A03EC
2. Attempted to read or write protected memory. this is often indication that other memory is corrupt.

I get these errors only when I have user created conditional formatting rules prior to deleting – I don’t want to delete all conditional formatting rules using FormatConditions.Delete(). Further, I can’t use FormatConditions[index].Delete() because I don’t have a index reference for the one that was created from the application.

Note: I have checked the Trust access to the VBA project object model.