Here is why Time Machine will not work with its external unit

Mac users who trusted Time Machine went through an approximate transition a few years ago when Apple emigrated away from their HFS+ format used to encode hard and SSD discs to the modern, more capable and more robust APFs format. During that change, many users had trouble discovering the formats in which the destination volumes of external machines had to be to allow backup copies.

That is in the past, and now we are in an APFs world, with a time machine that admits the volumes formatted in HFS+ or APFs. But it can still be bitten by an old album that works well with its Mac and has done it for years, but that is based on a Windows oriented format: Exfat or NTFS. Apple admitted these formats (and still does) to allow compatibility between macOS and Windows. Or, you can buy a unit today that is formatted by default for Windows, probably in Exfat, and not thinking about reformatat it before putting it into use with your Mac.

When you go to System configuration > General > Hourly machine and click OptionYou will see that all exfat and NTFS volumes appear in the Exclude backups List together with any element that added manually and the machine volumes of all time mounted on his Mac. However, unlike the elements he added, when he selects the external volume, keep in mind that the remove button (a less sign at the bottom of the list) is attenuated and cannot be click. (It is difficult to see in the screenshot that is a lighter gray than the add/sign button).

The solution is to make a backup of the external volume, reformat it as APFS and restore its content. Then, you can use Time Machine for the routine file. If you are not using Time Machine, here are all the details on how to start with the built -in cup for macOS. And check our selections to get the best hard drive for your MAC.

This Mac 911 article answers a question presented by Macworld Reader Sally.

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