Available space does not change

Are you using Time Machine to do those backups? Does the Time Machine panel of System Preferences show a recent successful backup? If both those are true, have you changed many files? Time Machine only consumes much additional space if files on your Mac change.

Is it possible that Time Machine is deleting enough older backups to keep the total space the same?

Oliver Hoeveler wrote:

I do not think so.

Do you think so based on your following statement or because of something else?

As the TM panel does not show the disk space as no backup is running.

It won't, as the "sparsebundle" file containing your backups isn't mounted when Time Machine isn't running. You can mount that yourself. Select your Time Capsule from a Finder window sidebar, then the "Data" volume (presuming you didn't change its name). In the Data volume double-click the "sparsebundle" file to mount it. You should now see space reported in the Time Machine panel of System Preferences.

If you have deleted files from your Mac in the past.....these files will usually stay on the Time Capsule for some period of time. Could be months or many months.

But, at some unknown point in time....Time Machine will delete those files from the backups to clear space. When it does that, you would think that the sparsebundle would then show more available space on the drive....but it does not do that.

Sparsebundle files are curious items......they "grow" as files are added, but they do not appear to shrink when files are deleted.

For example....The sparsebundle file might have grown to 100 GB. But Time Machine deleted 5 GB. The sparsebundle file will continue to show as 100 GB until the space that was gained when the files were deleted fills back up to 100 GB. At that point, the sparsebundle file will start to "grow" again.

This is very likely what is happening on your Time Capsule at this time.

If you have been checking your backups by going into Time Machine and everything appears to be normal, then I would not be concerned.

It is possible to "shrink" the sparsebundle file and have it display the actual space that is being used. But, you have to use Terminal commands to do this.

We can give you the commands to "compact" the sparsebundle if you want them....but unless you are an experienced Mac programmer, I would stay away. The Terminal is a very scary place.

Bob,

Yours is obviously the right answer. I was thinking too much about the situation where the sparsebundle file was still growing as additional files were added.

If Oliver tells us that he has never deleted any files from his Mac and there is plenty of free space on the Time Capsule.....then I am stumped on this one and we'll call in Pondini to rescue us all.

I am stumped. Cannot recall ever seeng an issue like this unless some files have been deleted along the way.

Could this be a case of a size-limited sparsebundle file? However, I thought that at some point Time Machine gained the ability to resize those as needed.