I set up a wireless connection with Calibre under Connect/Share. The device icon appeared & I selected 1 book as a test to send to my Nook HD+. The device icon then disappeared. On my Nook HD+ is says "Syncing with Calibre...Receiving books from Calibre & the name of the book that is being received. It has been sitting that way for about 15 minutes. Under Connect/Share it looks like I am still cnnnected but I have no device icon on the taskbar & nothing else seems to be happening. Should it take this long to get 1 book?
Do make sure the server is on, calibre companion could be trying to connect but the server is off. I set mine to turn on automatically whenever calibre is open.
If your server is on, the first time you use calibre companion takes awhile, it has to find your server and sync up what you have on your device to what is in your library. It will also create your on device library, etc on your device to include all the metadata, covers, etc for what you have on device. It does take awhile that first time. How long?
It depends on how much you have on your device. Calibre is scanning to see what you've already put on your device and compares to make sure it is the same book that is in the calibre library. It can take several minutes. I had 2000 sideloaded books on my device and it did take a long time (about 30 min) to find them all and to sync them up the first time when I unstalled and reinstalled. It might have taken even longer if the info hadn't been there prior to the update. After that it doesn't take so long, generally only a couple of minutes max for all my books to sync. .
However, if the device icon disappeared, you might have lost connection. You might have to reconnect and try again. Don't try to transfer books until after the sync is finished.