Using a file server with multiple drives you'll run into a problem as soon as you add a card reader.
A 5-in-1 card reader will occupy five drive letters while you insert f.e. a micro SD card into it.
Drive letters will end at 'sdj'. No luck with 'sdk' and so on.
Noticed this while running Dunfell 2.8.1 and 2.8.4 so far.
I have used USB sticks and an adapter SD to micro SD for verification of the problem.