[DMcCunney]

Calibre and my master library live on an HP quad core desktop box running a current Win10 Pro release.

My primary eBook viewer device is a 7" Android tablet running Android 4.4 Kit-Kat with FBReader as the eBook viewer software. Books reside on a 32GB microSD card in the deivice.

MTP is a non-starter on the device, so the best way to update the on device library is to shut down the tablet, pop the microSD card, put it into an adapter, and plug it into a USB port on the desktop, then use Connect to Folder to access it.

This worked yesterday, and fails today. The adapter can be plugged in to a variety of ports on the desktop. There are front facing USB2 ports, 4 port and 7 USB2 hubs in rear-facing ports, and rear facing USB3 ports provided by a USB3 PCI-e card. (The HP did not come with USB3 on board.) The 4 port hub connects my keyboard and mouse. The 7 port hub holds an assortment of thumb drives.

I can plug the adapter into any USB motherboard port or the 7 port hub. Win10 will see it, and it will appear as drive N:. I can drill down into it in Windows Explorer, and run CHKDSK which it passes with flying colors.

If I run Calibre and say Connect to Folder with that device plugged in, Calibre hangs and must be killed. I must reboot the machine to get Calibre to Connect to Folder on a local drive once this has occurred.

This worked yesterday. It fails today. I have changed the adapter the microSD card is in, tried plugging it into motherboard and hub USB ports, and moved the 7 port USB hub to a USB3 port provided by the add on USB3 card. It doesn't matter. Calibre hangs doing a Connect to Folder if that drive us plugged in. (I also installed a new Calibre point release while trying to resolve this with no difference in behavior.)

Can anyone suggest a way to debug what is occurring? There have been no significant changes on the desktop or tablet sides between it working yesterday and failing now, so I'm scratching my head in confusion.

Thanks in advance.
______
Dennis