Interesting. I ran into a host of problems last night, right after the brand new backup was done. And maybe not out of the woods yet!
First, since the time capsule drive for Time Machine was named “data”, I decide I wanted to change it. Because I have other “data” related names and wanted to make it more obvious which was which.
So I already had an external drive named “Main Data”, which is where my photos and iTunes stuff is instead of on my Mac Mini’s drive. And I have “Data Backup” which is a copy of that. So I renamed “data” to be “TC Data” (for “time capsule data”).
A little later, I get a popup from BackBlaze saying I was running low on storage - a problem I had previously and there is a long thread here about it. But this time I had plenty of storage on the internal SSD (well over 200 GB!). A short time later I get a popup about mail problems and running out of room on my “home” folder or something like that. Tried restarting mail, but that didn’t help.
Eventually I just decided to shutdown and start up again in hopes that would work. Well, first it wasn’t able to close all the apps, so I had to force quit. Then when I tried to shutdown again, the screen went dark, but I had the little spinning color wheel that just kept going. Finally gave up and held the power button down until it shut off. Waited 30 seconds and restarted. Seemed fine at that point.
However, before finishing for the night, I shut down again so my backup schedule wouldn’t run, just in case there was something corrupted - didn’t want to ruin the backup. Might do the same thing tonight.
So this morning I start it up, seems fine, but I do get a message saying it had to restart because of a problem. Not sure what that referred to since it didn’t restart. Could have referred to when I forced it to power down, but since I had started it again last night after that, I shouldn’t get that message for this bootup! So that’s still a mystery.
Then a little while ago, I saw that the last Time Machine backup was late last night - the one that started from scratch. So it hadn’t backed up anything in a lot of hours!
Looked at the Time machine prefs and the disk still said “data” rather than “TC data”!
More checking showed that on the list of backup disks, it had both names! So I selected “TC Data” and it asked if I wanted to use both it and “data” or just “TC Data”. Chose the latter. Said it would “transfer” the info and that seemed to go quickly. Now it only shows “TC Data” as an option. No idea what the heck is going on - that is, why “data” showed before after I did the name change.
Not sure how to tell Time Machine not to back up the OS stuff, but I think I may just let it be as is for now anyway since it should make transferring to a new computer easier in the future. Would be nice if Apple had two services - one for “everything” but maybe set up an option in iCloud for keeping some old versions of data files.