A New install gets exactly 1 book (the users guide).
Calibre has MILLIONS of users (check the stats at the download site)
So, that leaves your system and you, doing something odd
Did you read the FAQs? The stickies at the top of this and the devices forum (this issue. Good plan to read them all
)
First of all we need to know on WHAT OS (and version) you are putting Calibre.
Then WHERE, your Library (folder) is: (usual defaults to your user folder)?
Right off the top, without any input from you, I would guess:
You put (allowed) the Library in a Google Drive (cloud) folder. That is a 100% incompatible place as it mangles the file/folder names. SEE stickies
Other Clouds (or NAS) can be used for BACKUP, but not for an active Library use. (and 2 way sync really is a race to disaster. Mirror is mostly safe.)