Don't let it get too full !!
Yup, cannot use the favourites to browse. Decided to do another clean install then try and back up again.
Slightly off-topic, but there are also TM problems in its space calculations
I have four external disks, one of which is dedicated to Time Machine, the other contain data. I backup a selection of data from each of these to the TM disk, and have exclusions on the internal disk as well. Not all disks are connected all the time. All worked fine in Mavericks
I upgraded from Mavericks to Yosemite.
In Yosemite, first occasion on which Time Machine runs after my photos disk has been mounted; TMs required space calculation includes data already backed up not just the delta. However, when it runs the backup it only copies the delta. Example:
Will copy (20.5 MB) from Macintosh HD
Will copy (Zero KB) from Photo Masters
Found 24224 files (273.06 GB) needing backup
295.78 GB required...
Copied 49 items (20.5 MB) from Macintosh HD
Copied 8 items (11.6 MB) from Photo Masters
Created new backup...
The 295.78 GB is the total already existing on the TM disk, the 11.6 MB was the correct delta.
Why is this important?
A. If the incorrect calculation is more that the free space on the TM drive then it will start deleting backups - so all my Mavericks backups were destroyed
B. TM won't auto-delete the most recent backup, so if the incorrect calculation plus the size of the latest pre-existing backup is greater than the size of the TM volume then you have to initialise the TM disk and start again - goodbye backups and I'm now into day three of rebuilding the first backup under Yosemite
Or how about this for arithmetic...
247KB of files to back up - 450GB required
; only 30MB actually backed up