Mac – Time capsule not backing up

Time Machine is using differential backups. That means your first backup is a complete backup which is same size with your drive. Starting from the second one backup will include changed files since last backup.

These Backups are accessible by finder. So you can easily find out which folders causes these big backups. After you find the folders you can manually exclude these folders from Time Machine Backup Options.

Some softwares may cause huge backups if they changes files last updated status like Dropbox Agent or similar. You may consider exclude folders of these softwares because they are already copied to the cloud.

This isn't normal, but you have two options:

1. Just wait for all the processing to finish or error out.
2. Help the process along.

In this case, an initial backup can take a long time, but the way to help the process along is to delete the .../whatever.inProgress file. You could also try backing up to a new drive to make sure it's not a problem with the Mac as opposed to a problem with the backup drive or just a lot of changes to reconcile.

See this other answer for details.

https://apple.stackexchange.com/a/65801/5472

In cases where you run into this repeatedly, you can either try to isolate what folder takes so long to back up. On a first backup, I've tried to exclude the Users folder (or several folders at the base of the boot volume if they have more than 10 GB of data) to make sure that the filseystem is OK and the backup drive is OK. At that point, you will see backups taking a minute or so for each incremental backup. You can then relax the exclusion list and know if it freezes, then you have a problem in a specific folder.

The other way to attack this is run disk utility (or another tool) to repair the directory structure or make a back up using another tool and wipe the drives / restore them from backup.