Time machine not backing up

You will need to let it work. Ejecting the backup drive prematurely will result in the need to verify and repair a potentially corrupted file directory before TM can even begin to back up. When it does, it will need to recalculate all over again, from the beginning. Expect several hours at least.

Thanks. Next please read If Time Machine remains in the “preparing” stage on Mac. The date of the current backup is today, so I'd be inclined to believe that it has not been stuck for several days.

Let it keep working for now. Give it at least several more hours.

$200 is a lot of money to spend for a $60 backup drive, but no matter. Provided it's not corrupted in some way, it should work.

You could use Disk Utility to verify its integrity (see below) but that would require interrupting a backup in progress, and you don't want to do that just yet. All hard disk drives fail—eventually—but to conclude that's the cause would be premature.

If a Time Machine backup takes longer than you expect:

"... open Time Machine preferences and turn Time Machine off, then use Disk Utility to verify your startup disk, external backup drives, and any other drives that you're backing up. You can turn Time Machine back on after your drives are verified or repaired successfully."

Disk utility doesn't show any external but in my finder it shows up but there is only few files in there and 2 disk which won't mount or have hardly anything in them. Not able to drag files to the folder or add a new folder. Now with Mac OS Catalina we know have instead of bash using zsh. Son and I were doing something to using terminal over a week ago to delete some internet files and we had to search zsh since bash no longer there. Not sure if that has anything to do with it. I did some checking on you tube again and with previous version they were able to force mount using the terminal. I also don't see the disc on my desktop like I do with my iMac disc but it is in the finder just not where it needs to be or not in the disk utility like you see here. I am confused what containers are and disc 1 and disc 2. I know I have a fusion drive but now everything has updated to the new system. Do I need to physical put the drive to my iMac to get this to work or just give up with the apple airport I just need those files off it if it is still there. It my entire family medical documents, photos, etc. This royally sucks! Now tomorrow I got to figure how to set up this WD back up drive at least I got $136 off the price at Office Depot and drive up pick up! Alot less than my apple tower I call it. Plus I am getting 8GB I could of gotten 10 GB but for $150 for 8GB is awesome price! My son has the macOS support essentials 10.12 book from his class you think it would be good to get the Mac OS support 10.15 book as this one seems to be outdated already with talking about containers and zsh instead of bash just name a couple new things that I have noticed.

My got stuck in preparing backup on my apple airport time capsule 3tb. For some reason I also lost all my major files on it can't recover it at all. When adding new files to the folder that is there it just removes it over and over again. Even when I add a new folder as well. Been at this for 2 days now. I actually order a WD 8TB back up drive tonight will be picking it up at tomorrow at Office Depot. I have had my my apple airport time capsule since I bought my iMac 2015 with fusion drive 1TB. But I am running Mac OS Catalina 10.15.4 I need these folders and files I had in on my apple airport time capsule which also is my 2nd wireless router that I use for my household. It was there not long ago as I had was cleaning up old files. I have many important documents, and photos. Especially the ones of my beloved husband who passed away Jan 1, 2019. Now its all gone because of what I don't know. I am usually pretty at good figuring this out myself. Just getting ****** lately and my son who went to college for this but now there has been many updates since he had the classes. We both been using google, and you tube to figure it out. But nothing has worked. How will this work with this new WD as I never used one with my apple products before. Plus will I need to keep this plug in all the time to keep it updating to it? I do have iMac 2015 27in and MacBook Pro 13in 2018 model. I am apple user all the way including a iPad Pro and iPhone 11 Pro max. Please help?

What matters is the contents of the backup drive, not the source volume. Typical backups contain millions of little files.

Consider the possibility the backup drive has suffered some degree of corruption, but you appear to be too impatient to accumulate sufficient information to even begin to draw a determination. If and when additional troubleshooting is justified it will be even more time-consuming.

The weird thing I had years of data back up on my airport time capsule since 2015. Never lost any back up files. But yesterday I noticed that all my files were missing but for a few. The back up thingy won’t mount. Also it won’t let me keep new folders. Or even drag from the trash folder that I had doubles in that I didn’t need anymore but didn’t fully empty yet. It just refuses let me add anything and when I try it does nothing. I even had tried to restart or shut down it freezes at times.

Once I get my WD 8TB backup drive I am going to take all my documents and photos and save to that. Not sure if I should try to back up to the new drive or should I try to reinstall Mac OS Catalina 15.4.1 even my MacBook Pro won’t even acknowledge any backups. I used it mostly for my iMac but usually able to see it from my MacBook Pro but would save things from there as well at times. Has my time capsule just gave up? Or is it corrupted? The internet still works on it still? Could of someone had hacked into or or got a virus on it? I do run free version malwarebytes and nothing has ever been found since I had my iMac since Dec 2015.

Please read Time Machine troubleshooting on Mac. Determine which, if any, of those descriptions apply to the reason it's not working.