I only have my Mac which is on Catalina 10.15.7 (and my iPhone SE if that helps). How can I backup using Time Machine without anything else? I want to install bootcamp and it says I should backup my disk but I'm not sure how with the resources at hand.
Saving two copies of your files to the same drive isn’t a backup type that will protect you from a Boot Camp error.
You’ll want to get an inexpensive USB drive to copy your critical documents. Then when you can afford a drive that’s at least as large as your internal drive, set up Time Machine so you are protected by automatic backups of the Mac data. Note, Time Machine does not backup Boot Camp.
The problem is not Bootcamp per se. The problem is that in order to install another operating system on your Mac, you need to have a dedicated partition for it. And in order to get that, you have to shrink the existing partition on your drive to make room for another one, and that shrinking can irreversibly damage your data. Disk Utility is pretty good about trying to do this intelligently and not include your data in the parts that get removed when the partition is shrunk but it isn't perfect.
So it usually goes fine, but you're rolling the dice which is why Bootcamp gives you that warning. So the problem with your idea is this: where's that backup going to be at? Because if it's going to be on your primary partition it's subject to the same potential corruption when the shrinkage occurs.
So backing your data up on the same drive is out. If you're willing to potentially lose your data forever then just roll the dice and take your chances, and if you're not you can buy a very reasonably-sized external drive to use for Time Machine for a fraction of the cost of a Mac/iPhone.
It sounds like you do not have a different storage device and cannot get one.
One way to backup your Mac is to use cloud storage, or cloud backup. In other words, you can use an online service to back up your data.
Is it a requirement that you create the backup using Time Machine? Time Machine requires a different storage device, so if you cannot get a different storage device, you will probably not be able to use Time Machine.
If you have a backup of all your data in the cloud, then you can restore your data from there if needed. If the whole disk containing bootcamp is corrupted, you will need some way to restore your operating system (basically, restore your computer to factory settings), such as a bootable USB drive or DVD drive with a macOS install disc. Once your computer is bootable, you can connect to the internet and retrieve your backed up files.
Examples of cloud backup providers include:
You may also be able to use a general online storage service, such as:
- Google Drive