While enterprise-level backup options may offer robust solutions for workgroups, Apple’s Time Machine service is a great backup option to use for a single machine since it preserves the OS configuration along with all user data and applications. However, if you have used several Time Machine drives over time, you may find OS X suddenly showing Notification Center warnings that there have been no backups for a given number of days.
This may occur even if you have a Time Machine drive or Time Capsule on-hand that you regularly and successfully use to back up your Mac.
Time Machine supports multiple disks, and when you attach a newly formatted drive OS X may ask whether or not you wish to use the drive for your Mac. You can also manually specify additional Time Machine destinations in the system preferences, including both network storage and local storage. Either way, if you end up with multiple destinations configured, OS X will revolve through them when running its hourly backups to ensure even distribution of your backups.
This means that if you have a working Time Machine drive attached to your system, OS X may successfully back up to it, but then attempt to back up to the other destinations you have configured. At first OS X will simply skip them, but after 10 days you will begin to see the Time Machine warnings appear.
Solutions: Find or remove
The solution to this problem will depend on your particular situation, but boils down to two approaches:
- Find the Disk
Finding and attaching the Time Machine drive that is mentioned in the warning will allow OS X to update the backups on it, and dismiss the warning. You can get more details about the drive by clicking the “Details” button in the warning; however, overall Time Machine will only give you the name of the disk, and often you may end up with non-distinguishable names like “Backup” or “My Backups” or “Time Machine Backups.”
- Remove the drive
If you cannot find your Time Machine drive, or if it has been repurposed or is otherwise unavailable, then your second option is to remove the drive from Time Machine. This approach has the benefit of preventing the warnings from showing, but also will not affect the status of the backups on the drives you remove (ie, they will not be deleted). With this, if you add the drive again, OS X will recognize the backups on it and offer the option to inherit them for the current system. This will allow you to essentially pick up where Time Machine left off with the backups for this drive.
I do a full monthly backup with Time Machine and a daily backup of personal data only daily with Tri-Backup Pro. Is there any problem with the Time Machine “No Backup for XX Days”?
The issue you didn’t explain is how or why you do a Time Machine backup only once a month. If the TM drive is connected to your computer all the time, TM will backup once an hour. If you only connect it once a month, TM will have backed up everything on your internal drive (wasting a lot of space in the process) waiting for the drive to be connected, which will then be a process intensive move of the backed up data to the backup drive. If this is how you operate, it suggests to me you don’t understand the purpose and operation of Time Machine. The whole point of TM is to provide constant backups so that you can restore a file or an entire drive from any point in time should the need arise—as it often does. If your drive fails for some reason between your monthly backups you will lose a lot of data, including software and system updates you’ve made in the meantime.
You don’t need Tri-Backup Pro if you use Time Machine properly, unless the data you are backing up is from one external drive to another. If your data is on your internal drive, Time Machine will back it up routinely every hour. Now you might use Tri-Backup Pro for additional backup, if you want some redundancy. But I suggest you leave your Time Machine drive connected to your computer all the time so that TM may work as it was intended to do.
By the way, Time Machine only backs up data that has changed or been added since the last backup. So it’s not making multiple copies of the same files—unless those files have changed. In which case you can access multiple versions of the files, which is an advantage TM has over standard clones.
You did not get it. Time Machine is always off. Always. So, no wasted backups at all.
I just do a Time Machine full (incremental) backup once a month as said (no problem if I had to update software; that can be done in minutes) and daily Tri-Backup Pro daily for documents as said.
That way I save lots of trouble, energy and disk wear. For me it is the ideal backup strategy, hands down. I wonder how many disks have failed due to the massive stress caused by Time Machine hourly backups!
I use a backup drive that I keep in the safe deposit box. I bring it home once a quarter and let Time Machine backup to it. The only problem with the notification is the notification itself. I have had mine go for 90+ days without any problems.
It that’s the only time you use Time Machine, like Max you are missing the point. And risking even more than he is. Time Machine is intended to run constantly, backing up to a drive that is always connected. In the case of a laptop computer that travels a little or a lot, Time Machine does it’s backups on the internal drive waiting for the external drive to be connected once the computer is back at home base. If you only connect the backup drive every month or three, you are using a lot of space on your internal drive to store the temporary backup files, not to mention all the overhead it takes to move that much data to the backup drive so infrequently.
The most effective use of a safety deposit box is for occasional clones of your boot drive, and even that should be in addition to a regular clone to a desktop drive. Restoring from a clone is much faster, and generally more reliable, than restoring from Time Machine. I have needed both from time to time—even a clone can be corrupted and being able to restore from several weeks or months in the past before the corruption hit your drives is very useful, not to say critical. Of course, an old clone in a safety deposit box might also be viable in that case.
But you don’t have to take my word for it. Check out Backing Up Your Mac: A Joe On Tech Guide, https://www.takecontrolbooks.com/jot-backing-up, by Joe Kissell, a well established expert on the Mac.
Thank you, Topher, for the deep dive into Time Machine arcana. Using multiple drives is one of the more difficult aspects of Time Machine. I’ll be saving this article.
The setup: two backup drive destinations. One is the live backup, one is offsite in fire safe. Swap the drives out every other week. Would love to find the magic plist that one could do a “defaults write …” to in order to increase the “No Backups for XX Days” warning threshold to 15 days, but have searched for years in vain. Anyone have an idea?
B.Jefferson Le Blanc said: ” If you only connect the backup drive every month or three, you are using a lot of space on your internal drive to store the temporary backup file”.
Does anyone have a link to an authority to prove that this assertion is true? It doesn’t make sense to me that MacOS would waste spacing caching backup files. When the infrequently-connected hard drive is plugged in, on Console I can see MacOS doing a deep dive comparing the Time Machine backup on the newly connected hard drive to the state of my internal drive, and then it starts an incremental backup. Metadata is being compared, I don’t see any reason to keep extra copies of the actual files around awaiting the next backup.
I keep an extra hard drive in a location 2,000 miles from home that I only visit every 2-4 months. While it is annoying to dismiss the “missing backup” notification every day, once I reach the offsite location Time Machine automatically does an incremental backup. I am then free of the annoying warning for about two weeks, after which they start up again.