I love Calibre. When it comes to converting my text from crude html to a fully-functioning, card-carrying member of the eBook community, it does the business. And I have nothing but admiration for my Kindle, and her close cousin, Kindle-for-PC (KPC). But, they make miserable dancing partners.
A whole afternoon and half the evening I've spent rebuilding my latest eBook in Calibre for the Kindle. First, I changed the cover. Not a huge change, but I needed to replace the book cover file with a new version. I tried changing just the cover and re-saving the whole shebang onto the disk. No luck. I started from scratch, removing the book from Calibre's database ("library") and rebuilding from my html file. That didn't work either - KPC was still picking up the original cover. I deleted the four Calibre-generated files from my disk and started from scratch in Calibre again. That worked. KPC picked up the new cover design.
Idly paging through the book, I found a typo. Not a big one, just a pronoun that needed to be replaced by a noun; what I had written was ambiguous. I went back to square one, deleted the Calibre-Kindle files from the disk, removed the book from Calibre's library and recreated the book again.
Into KPC I scurried, with my fingers crossed. Imagine my surprise when that pronoun appeared, bold as brass on my screen. How could this be? I had changed it, scrubbed everything, started from scratch. But still, KPC was somehow picking up the old version of the book, a version which I had deleted from the disk. After my obligatory apoplectic fit, I reasoned that, far from dancing to Calibre's tune, KPC was merrily displaying its own cached data, trying to be smart, to reduce the time to load.
I rebooted. And KPC picked up the new version of the book from the disk. So I suppose when I changed the cover all those hours ago, all I had to do was clear KPC's cache by rebooting, and I wouldn't have had to rebuild the book from scratch.
UPDATE: It's a couple of days later and today, I changed the source file to include an ISBN for the Amazon Kindle version distinct from the Smashwords version. Just 3 digits. I edited the source file, saved it deleted all the files previously created by Calibre and recreated the .MOBI file using Calibre. At this stage, it's almost 11 pm and I've gone through the process 10 or 15 times without success. I tried rebooting, I tried deleting all my cookies. I've tried sacrificing a cockrel to the god Baal. Nothing works.
ANOTHER UPDATE: Thanks to Kovid Goyal, the developer of Calibre, who emailed me directly with the solution, everything is as it should be again. The fault, it seems, was with KFPC, not with Calibre at all. What Kovid advised me to do was to open KFPC and remove the book file from the device. Then go into Calibre and save the book files to disk again (placing them in a folder other than My Kindle Content).
I then double-clicked on that saved .MOBI file and KFPC picked it up and it's correct.
A thousand apologies, Kovid, for accusing Calibre of having a bug (perish the thought). And thanks for coming to my aid. I owe you a pint. Expect the PayPal equivalent this evening.
I now officially hate Kindle-for-PC, and will go find Kindle Previewer as you suggested.