I have seen multiple posts on the web trying to decipher the OutOfMemoryException thrown by Management Studio (SSMS) while executing a user query. Contrary to popular beliefs, this is not a SQL Database Engine Out of Memory condition. This is a client side OOM condition thrown by the .NET runtime while trying to receive the output of the query from the Database Engine. More often than not, the culprit is a large number of rows returned by the query submitted by the user.

A lot of times the error can be circumvented by using the TEXT mode output of SSMS. The error is a .NET Out of Memory exception pointing to the Management Studio running out of available physical memory. The GRID output requires a .NET GridView control to be created where as the Text mode output uses a TextBox to store the output returned by the database engine. The amount of memory consumed by the GRID is higher than a TextBox.

It is always advisable to store the output of a query returns a large number of rows into a file (CTRL+SHIFT+F) or use SQLCMD to generate the output into a CSV/TXT file. This would help optimize the memory usage on the box that is executing the query and also prevent re-execution of the query due to client box out-of-memory conditions. IMHO I cannot fathom the need to output a million rows in the GRID view because it is not possible to parse the output unless you put that into a flat file! Hope this sheds some light on this common misconception.

Once such issue is mentioned below:

Reference: OOM error when we access Schema changes report from SSMS – Microsoft