[Tarasug]

Having become totally fed up with iBooks frequently crashing, I installed the full version of Marvin on my iPad Air (iOS 9.3.1) and installed the plugs ins for Calibre etc. Calibre recognises the device, but when I try to download books from Calibre, I receive a message saying that the format is not recognised. All my books are ePub, and I have no problems loading to Marvin from Dropbox, but as I have several thousand books stored on Calibre I really don't want to save them all to Dropbox as well.

Can anyone tell me what I may be doing wrong?

I have the same problem. I can't connect my iPad to my Windows 7 machine to transfer from Calibre to Marvin. The PC recognizes the iPad, but Calibre won't recognize Marvin (and I have re-installed the plugin several times.)

I'm loading my books via DropBox as well. It helps to have my Calibre library in my DropBox (I use it for almost nothing else these days.)

There is an easy way to access your Calibre Library from Marvin. In Calibre, activate the Content Server and take note of the address. Open Marvin, and in the bottom right corner of the page tap ‘Get books’. Follow instructions (choose opds) to add calibre using your calibre content server address ending in /opds.

Now, when you want to download from calibre, go again to ‘get books’ select opds, then select calibre in the local network list that opens. You can then download and browse your calibre library.