I have a older iMac running High Sierra. It has a 1TB hard drive. I wanted to use time machine to back up. Santa Claus gave me a 1TB Samsung USB drive for Christmas. When I try to create a back up with Time Machine, I get an error message that says I don’t have enough space on the external drive to create a back up... “Back Up Failed,”
What am I doing wrong? How big of an external drive do I need for a computer with a 1TB hard drive?
iMac 21.5″, macOS 10.13
First, the External Hard Disk has to be formatted using Disk Utility to Mac OS Extended (Journaled). Almost all EHDs come pre-formatted from the factory for MS Windows so you need to change that first. Once it has been formatted you can begin using it for Time Machine.
To answer your questions about the size, the minimum size should be at least 2-3 times size of the amount of data being backed up. So check About this Mac - Storage to see how much is currently stored on your computer then multiply to 2 or 3. 1 TB may be enough if you have a small amount of data, however 1 TB is generally too small. My Time Machine back up is 4TB and it is currently about 50% full.
EHDs are inexpensive, you can get an excellent high quality External Hard Disk for about $179 that is 4TB. What most experienced users like are OWC Mercury Elite Pro due to their reasonable price, very high quality, ease of maintenance and the service OWC offers.
First, the External Hard Disk has to be formatted using Disk Utility to Mac OS Extended (Journaled). Almost all EHDs come pre-formatted from the factory for MS Windows so you need to change that first. Once it has been formatted you can begin using it for Time Machine.
To answer your questions about the size, the minimum size should be at least 2-3 times size of the amount of data being backed up. So check About this Mac - Storage to see how much is currently stored on your computer then multiply to 2 or 3. 1 TB may be enough if you have a small amount of data, however 1 TB is generally too small. My Time Machine back up is 4TB and it is currently about 50% full.
EHDs are inexpensive, you can get an excellent high quality External Hard Disk for about $179 that is 4TB. What most experienced users like are OWC Mercury Elite Pro due to their reasonable price, very high quality, ease of maintenance and the service OWC offers.
If you don't need backups so that you can go back and get a erroneously deleted file you can use the drive you have to make a bootable clone of your boot drive with Carbon Copy Cloner . You can then program it to do an incremental backup at the interval of your choice and it will copy only those files that are new or changed. It will delete files off the clone that are no longer on your boot drive.
Personally, I use both Time Machine and a clone. My family photos are too valuable to leave it to only one backup.
I agree wholeheartedly with rkaufmann87 on the OWC drives. I have several.
Thanks for your reply. I understand why it won't back up properly.
I had been hoping for a simple solution to backing up. The "Backup" instructions might have included this information.
I'm not a power user or a professional. I don't really need hourly back ups. What I was looking for was an occasional back up of my hard drive, especially before an major system update.
I appreciate the time it took you to review my issue and give me an idea how to solve the problem. Thanks!
Your welcome.
time machine
