Steam wont install full backup from HDD

[G9XFTW]

For many years I have backed up my steam library on an ext HDD. For some reason in certain games it will only install like say part of the actual game from the HDD and then proceed to download the rest. The 3rd world internet speeds dont help and it really causes an inconvenience.

 

A recent case: Rocket league comes to around 7GB, it will install like 2.2GB from drive, and mind you, this is the latest backup of the current version. Then the remainder will be downloaded. Why dafuq do I waste 7GB space when its not even gonna be installed from?!

 

and oh boi, when it comes to bigger games. ARK, ASSASINS UNITY, SIEGE. son of a bitch.....

 

How do I remedy this inconvenience of having to download the already backed up game?

[mark_]

Recently, I am facing an issue with the Steam as it is not able to install the full part of some games. It can only install and backup of some part of the game. I have also tried to contact g-suite tech support to ask about this. However, may I get any solution to fix this issue with the Steam?