[SuzDavid]

Hi, Charles. Thanks for the quick response. Sorry I took so long; I had a family emergency. I just have a few questions about the questions you posed:

chaley: 'Also check that you really have V3.5.6 installed' ... 'What does Google Play say? Does it think CC is installed? If not, try installing it again.'

Upon trying to start the 'updated' CC on my Samsung tablet, the error message was '[CC] is not installed.' Google Play did Not think Calibre Companion was installed on this tablet.

I'm not 100% sure, but I think the update I originally downloaded to the tablet was, in fact, V3.5.5. I must have tried to re-download the update, which by that time was V3.5.6, because Google Play now shows CC V3.5.6 is installed on the tablet but there is no change in the crashing behavior.

chaley: ' "The "nuclear option" is to uninstall and reinstall the app. Depending on how many books you have on the device, this path could be somewhat painful, but it is the easiest and most certain path forward.'

I have more than 800 books in the Calibre Companion library on the tablet. I don't use any special settings (no subsets or different libraries) other than to sort by author or sometimes by title.
By 'painful,' did you mean that I would have to re-import all the books? Or just that I would lose any special settings I had?

If I would still have my basic library of books viewable in Calibre Companion after I uninstall and reinstall V3.5.6, then I have no problem with doing it that way.

If uninstall/reinstall of CC would mean having to re-import all the books, I would want to at least try the other options.
Before asking about pursuing that, I'll wait to hear from you about the 'losing my library' question.

Thanks again for your help.
~ Suz D.