BSONObj size: 27137194 (0x19E14AA) is invalid. Size must be between 0 and 16793600(16MB)

I’m inserting a document in MongoDB using C# MongoDB driver. A document consist of just 78 collections/lists. I found the following exception when document is inserting in mongo:

"Command findAndModify failed: BSONObj size: 27137194 (0x19E14AA) is invalid. Size must be between 0 and 16793600(16MB)"

I don’t know why size exception is throwing.

I do not fully understand the following:

If you mean that you try to insert one document composed of 78 collections/lists. What is the content of those 78 collections? If you really try to insert 78 collections as a single document, then I think the error is quite normal.