WD Elements working fine but not recognized in another computer

I just bought a 1 TB external hard drive yesterday. I plugged it into my sister’s laptop to copy files and it worked.

This morning, I was going to ask my friend for files but when he plugged it into his computer, it wasn’t recognized/wasn’t being read. I copied files from him before using a 500gb external hard drive and no problems there.

I panicked for a bit because I thought my hard drive might not be working anymore. I tried it in my personal laptop and in my work desktop and both recognized it. 

What could be the problem here?

Thanks and I hope someone can enlighten me on this matter!

If you have the Elements portable, it might not be receiving enough energy from the PC. Avoid using extension USB cables or USB hubs. 

If it’s a desktop sometimes using a USB port on the back works better also.