[margaretredhead]

Suddenly I find that Calibre cannot open the books in my main memory, or download them to either of the Kindles that I have. I keep getting a message `cannot connect to device`, or that the books don't have a format that my device recognises. I know that some of the books I have are in AZW3 format, but most of them are Mobi, which I had no problems with before. I am a complete Luddite with computers, but had no issues before. Sometimes I get a message to tell me that Calibre can't find the file the particular book is in & suggests that I might have moved the file & to try & find it. I haven't moved any files, so what do I do? I have tried uninstalling Calibre & then re-installing, but still no luck. Help!!!