This is a reasonably fast computer, 4.10 GHz 64-bit dual core processor, 8GB RAM, system drive is an SSD, SATA hard drives, clean recent Windows 10 full installation (not upgrade). There is no performance degradation anywhere other than Calibre startup after reboot. The computer will go from power-off to reading my email in 22 seconds.

Yes. That is what the program is for -- to manage the collection. It is not loading the ebooks themselves, only the books' metadata which points to the actual books on a different hard drive.

Yes.

Here's what happened.

1) I renamed the directory where the actual eBook files are kept.
2) I did a power-off reboot.
3) I started Calibre.
4) Instead of the usual 3-5 second load time (when not loading after a fresh reboot) it loaded in two and a half seconds. I closed the program.
5) I renamed the directory back to its normal name that Calibre is configured to look for.
6) I started Calibre again. It took 25 seconds to load, instead of the usual 3-5 seconds. This was NOT following a fresh re-boot.
7) I closed Calibre and re-started it. It took the normal 3-5 seconds to load.

I am unclear about what you mean when you say "Loading up your particular eBook file." Calibre is not a program for reading or editing eBooks (it can do those things but I don't use it for that). It is primarily for storing metadata on each book and connecting to my Kindle and transferring files to and from the eReader, and editing the metadata. It is useful for converting eBook file formats, say from epub to mobi. But none of that can be done until the program finishes loading, normally 3-5 seconds, or in my case 55 seconds after a re-boot.

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tanstaafl.