Let's say I am nearing the limit of space on my backup drive. So I want to delete backups or versions before 6 months ago. Is that possible through time machine? How do I do that?
This is the message I'm getting now!!! (Panic) Why is this happening? How do I stop it?
The backup disk is full.
Time Machine deleted one or more old backups to make room for new backups. The oldest remaining backup is: Feb 4, 2012
To avoid deleting additional old backups, open Time Machine preferences to select a different backup disk.
There doesn't seem to be a way to delete multiple backups via the starfield. You could use Terminal and tmutil delete to quickly delete multiple backups:
Make sure the backup disk is mounted (entering the starfield and then exiting it should work)
Navigate to the folder that contains the backups in the Finder. (I don't quite remember, but I think you get there by double-clicking on the backup disk on the desktop, then Backups.db, then a folder with the name of the computer being backed up.)
Open Terminal and type sudo tmutil delete (the space afterwards is important!)
Select all the backups that you want to delete and drag them into the Terminal window. That will automatically insert the filepaths for you. Then press return.
You will be asked for a password. That's your account password, the one you use to log into your computer. The characters won't echo, not even as dots or asterisks, so just type it carefully and then press return again.
Providing one answer to my own question would be is to start over (losing my history). I've done this before and IIRC:
Turn off Time Machine. System Preferences > Time Machine > On / Off switch
Open Disk Utility. Applications > Utilities > Disk Utility
Select the current Time Machine Hard Drive
Select Erase Tab
Choose Mac OS Extended (Journaled)
Open Time Machine
Click Select Disk button
Select the Hard Drive you just erased and click Use Backup Disk
Turn on Time Machine if it isn't turned on already.
I'm not going to select this as the answer, since the goal would be to save the history but it will give someone more space if that is the reason they are asking this question. Also please correct or edit the steps if you take this approach.
Enter the Time Machine starfield (right-click on the Dock icon and click Enter Time Machine, or click on the menu bar item and click Enter Time Machine)
Navigate back to the backup you would like to delete (by using the timeline on the right side of the screen or the arrows near the bottom).
Click on the gear icon at the top of the window—there's an option there called something like Delete Backup or Delete Entire Backup (not Delete All Backups Of This Item). You might be prompted for an admin name and password.
Depending on how much has changed from that backup to the adjacent ones, you might have to delete a few before you notice a difference.