[WJCronon]

Thanks, davidfor. Again, I really appreciate your good work and your willingness to help with this. I'm pretty sure I had in fact previously deleted all the plugin components you list in your most recent post, but just to make absolutely sure, I deleted the *entire* calibre folder from the Mac OS X Library/Preferences folder, so that the entire folder had to be rebuilt from scratch when I reinstalled calibre 2.1.0. Once calibre had done this, I reinstalled the two plugins, and got the following error report, close to but not quite identical to the one I shared above.

I tried turning on the debugging routines in each plug-in in turn, but each time got a "Device already detected" message saying that "A device (IOS reader applications) is already detected by calibre. If you wish to debug the detection of another device, first disconnect this device." (This note continues below the error report.)

calibre, version 2.1.0
ERROR: Error: Error communicating with device

database disk image is malformed

Traceback (most recent call last):
File "site-packages/calibre/gui2/device.py", line 86, in run
File "site-packages/calibre/gui2/device.py", line 501, in _books
File "/var/folders/vz/zhdqchxj0xv1fb7x_f2_x7nr0000gn/T/calibre_2.1.0_tmp_wODM4A/vjigGL_ios_local_db/Marvin_overlays.py", line 310, in books
DatabaseError: database disk image is malformed

But here's one additional piece of information that may be suggestive. I just tried connecting my iPhone to calibre 2.1.0, since it also runs Marvin XD, albeit with a much smaller number of books. It connected with no problem and I was able to load a book with no difficulty. The difference may be that my iPhone has just 500 books on it, whereas my iPad has more like ten times that number. Is it possible that your new plugin is somehow capacity limited in a way that the old plugin under calibre 1.48 was not? I know that one *possible* solution may be to blow away Marvin XD on my iPad and try to rebuild its library, but given how risky and time-consuming that project will be--I'm going to be very unhappy if I do it and then discover that I can't rebuild the collection and can't go back to calibre 1.48 either--I'd really like to feel confident that that will address the problem.

I hope all this information is helpful to you. Thanks again.

P.S.: For what it's worth, I just deinstalled calibre 2.1.0, reinstalled 1.48, backloaded the old plug-ins, and the iPad is working fine once again.