Requirements: Max 2016 + Ext1/2 + SP3. Max 2017/18
This MCG will blend the last few frames of your (vertex) animated mesh so that it will create a seamless loop. Works directly on your mesh as a modifier, no need for 'cloning' around. You can also adjust Start/End of animation easily.
Installation:
https://knowledge.autodesk.com/support/3ds-max/learn-explore/caas/CloudH...
Then can be found in modifier dropdown list.