Library installation procedure not recognising external drive

[kingzo]

I was going through Installation procedure to put the library for my newly purchased Amplesound Upright Bass library onto an external drive [Sandisk Portable SSD] currently attached and visible on my iMac OSX 10.13, but the installation process is not recognising this drive (it recognises the OSX internal and 1 other external drive). I also have a SanDisk Extreme 900 drive attached and although both external drives are visible on my desktop, only the SanDisk Extreme 900 drive is available to download to.
Not being familiar with the way Amplesound products work, can I solve this by installing the library on the visible external hard drive and then copy over the library to the hard drive that is not currently recognised?

[Liang[AmpleSound]]

@kingzo

Could you specify the file system formats of these 2 external drive? It should work if you install the library on the visible drive then move the library to the other drives and change the library path in Settings.

[kingzo]

Thanks for your response. Both drives are APFS, used exclusively for my iMac, so no logical reason for one not to be recognised. After 2 reboots, issue disappeared and both drives were available. Never had any previous issue with either of these drives, but hey ho, computers eh...
The Library I then downloaded from Amplesound’s email link was not up to date (giving errors 7, 14, 21 when opening plugin) so they sent me a new link which worked. So all good now.