Problems with time machine back ups

Prior to Catalina my Time Machine backups would take a few minutes - it now takes 2 - 3 hours. As soon as one back up finishes it starts another one. It's backing up continuously. The device is getting very warm.

Hello eddie0110 and welcome to Apple Support Communities.

I see you're having an issue with a Time machine backup not completing on a Time Capsule after the Catalina update.

You'll want to let the backup complete. By stopping and starting it, you're actually causing the backup to consume more space.

Cheers.

I have this same issue on my 2017 13" MacBook Pro, since upgrading to Catalina. I thought it might be a compatibility issue with my Synology NAS (Time Machine backups previously worked flawlessly for 2 years before Catalina) I bought an external hard drive to test, and shared it as a Time Machine volume from my iMac Pro (from the Apple sharing settings) It sees the drive and starts the backup. However, once the progress bar reaches 100%, the status message changes to "Backed up: xxxGB" and the amount continues to grow. The size it's reporting is WAY beyond what it historically took - it's up to 600GB now, and my total used space is only 175GB. It almost seems like Time Machine doesn't know it's time to stop, so it keeps writing new data.

Any other advice on this issue? None of the posts here really address the problem...Thanks!

Encausticcello - not sure this will help but sharing my experience. 2013 MacBook Air & Airport Time Capsule 5th Gen 2TB. After speaking to Apple Support tried starting in Safe mode (no improvement in backup performance) then running First Aid on the MacBook (again no improvement). The following day a Time Machine message appeared. Not the exact words but along the lines of "Time Machine has reviewed your back ups and a new backup needs to be taken. You will no longer be able to access previous backups". Time Machine then deleted all previous backups and did a complete 175GB in 3 hours - it's been working fine since - but it still shows "Backed up xxxGB." I don't know if either of the remedial actions triggered the backup review or if its completely coincidental. Maybe the Apple guys can figure out how its triggered as it seems to work. Apologies if no help at all.