SQL server 2012. Exception: attempted to read or write protected memory (MS.VS.OLE.Interop)

Are you attempting to edit a SQL 2014 database with the 2012 version (or earlier) of SQL Management Studio?

You can determine the SQL version of your database by running this query against your master database:

SELECT @@VERSION

I had the same problem and I was able to direct edit tables ('Edit Top 200') by installing and using SQL Server Management Studio 2014. Even if both your DB and Management Studio are version 2012, it might not hurt to upgrade Management Studio.

I have also faced the same issue. And I noticed one thing that if you are using SQL database newer then the SQL management studio version, You will received that message. To overcome this issue just install SQL management studio equal or greater then version of database. i.e if you have SQL 2012 then you need to install SQL management studio 2012 or 2014.