I just did a fresh install of OSMC 2017.8.-1 on my ATV1.
When using the MyOSMC app store to install Samba, it doesn’t work.
No response at all when you select samba server for installation and click Apply.
I CAN successfully install Samba Server via cli with:
sudo apt-get install smb-app-osmc
But the app store gui doesn’t work.
I think this is because I ripped the update service from Apple TV. App Store uses some of these modules, so won’t work as expected anymore on Apple TV.
I suspected as much.
I figured that I may as well post, so that anyone else who cares, knows how to manually install it. 
Using the Jan 2017 install, and disabling auto updates is te best idea anyhow, unless you are running without Crystal HD (or as a headless server)
If you still depend on CrystalHD acceleration, then this is quite correct.
After my ATV1 started to reboot over and over I had to do a re-install. However, I can’t access the store and when I tried to manually install Samba this is what happened:
osmc@osmc:~$ sudo apt-get install smb-app-osmc
Reading package lists… Done
Building dependency tree
Reading state information… Done
E: Unable to locate package smb-app-osmc
Can anyone help?
Run sudo apt-get update first.
Unfortunately that didn’t work:
osmc@osmc:~$ sudo apt-get update
Fetched 2,023 B in 19s (106 B/s)
Reading package lists… Done
W: There is no public key available for the following key IDs:
AA8E81B4331F7F50
osmc@osmc:~$ sudo apt-get install smb-app-osmc
Reading package lists… Done
Building dependency tree
Reading state information… Done
E: Unable to locate package smb-app-osmc
Check you have the APT key installed.