After interrupting "preparing backup" several times, unable to see time machine in finder
I've been using an old Time Capsule as a backup drive, after many years as a router. Recently it has been unable to backup; it's stuck in "preparing backup". I tried stopping and retrying; I tried removing it as a backup disk and then adding it back. When I removed the Time Capsule as a backup disk, I re-selected it under "available disks", and the name changed a little, suddenly using the name of my computer's internal drive (late 2015 iMac). As an added new backup disk, it had a message "waiting for first backup". (That freaked me out.)After reading a bunch of Bob Timmons' suggestions, I left it overnight. It stopped, but no backup was recorded. I removed it again, and re-added it from the list of available disks, where it had its old name. Seven hours later (trying ethernet), I again stopped the "preparing backup", thinking I should go into Time Machine in Finder to throw away any "in process" files. I could see the Backups.backupdb folder, which had a folder with my computer's name, but it contained no files! After restarting and talking to Apple, my Time Capsule is still showing up in Finder as "shared", but Time Machine no longer appears under "devices". When I enter Time Machine via system preferences, I see the old backups. This is all complicated by my using OS 10.13.6 (long story), and that the Time Capsule is full. Hope this makes sense. Bob, are you out there?? Thanks!
iMac 27″, macOS 10.13