# WD My Book for Mac Backup Disk Not Available **URL:** \ **Category:** External SSD for macOS\ **Created:** [April 17, 2018, 5:20pm UTC](https://forums.sandisk.com/t/wd-my-book-for-mac-backup-disk-not-available/412401 "2018-04-17T17:20:32Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Mspiege23](https://avatars.discourse-cdn.com/v4/letter/m/3be4f8/32.png) [@Mspiege23](https://forums.sandisk.com/u/Mspiege23)\ **Post date:** [April 17, 2018, 5:20pm UTC](https://forums.sandisk.com/t/wd-my-book-for-mac-backup-disk-not-available/412401/1 "2018-04-17T17:20:33Z")
When I try to initiate a back up from my iMac desktop running version 10.13.2 (High Sierra) to My Book for Mac (3T) external hard drive, I keep getting the message that the “Backup disk is not available”, even though the external hard drive is plugged directly into the computer. This used to run fine but over the last year or so it has become more difficult to make back ups. I don’t want to lose the data that is currently stored on the external hard drive. Hopefully, there is a way to work around having to restore the hard drive. Please help. ---
**Author:** ![DonaldKepler](https://sea2.discourse-cdn.com/sandisk/user_avatar/forums.sandisk.com/donaldkepler/32/54344_2.png) [@DonaldKepler](https://forums.sandisk.com/u/DonaldKepler)\ **Post date:** [April 18, 2018, 6:34am UTC](https://forums.sandisk.com/t/wd-my-book-for-mac-backup-disk-not-available/412401/2 "2018-04-18T06:34:41Z")
So how do you initiate a backup I mean are you trying to make Time Machine backup but unable to do so? Is your Macintosh HD APFS or HFS? ---
**Author:** ![Mspiege23](https://avatars.discourse-cdn.com/v4/letter/m/3be4f8/32.png) [@Mspiege23](https://forums.sandisk.com/u/Mspiege23)\ **Post date:** [April 19, 2018, 5:11pm UTC](https://forums.sandisk.com/t/wd-my-book-for-mac-backup-disk-not-available/412401/3 "2018-04-19T17:11:10Z")
Yes, I’m trying to make a back up through Time Machine and I keep getting the message “Backup Disk is Not Available”. I don’t understand what you are asking concerning HD APFS or HFS. What do they mean? ---
**Author:** ![DonaldKepler](https://sea2.discourse-cdn.com/sandisk/user_avatar/forums.sandisk.com/donaldkepler/32/54344_2.png) [@DonaldKepler](https://forums.sandisk.com/u/DonaldKepler)\ **Post date:** [April 20, 2018, 5:46am UTC](https://forums.sandisk.com/t/wd-my-book-for-mac-backup-disk-not-available/412401/4 "2018-04-20T05:46:46Z")
APFS is the default file system of macOS High Sierra in case your start-up drive is SSD. Further, Time Machine doesn’t backup APFS. Pls read about your solution here [https://support.apple.com/kb/PH25587?viewlocale=en\_US&locale=en\_US](https://support.apple.com/kb/PH25587?viewlocale=en_US&locale=en_US) ---
**Author:** ![Mspiege23](https://avatars.discourse-cdn.com/v4/letter/m/3be4f8/32.png) [@Mspiege23](https://forums.sandisk.com/u/Mspiege23)\ **Post date:** [April 20, 2018, 2:24pm UTC](https://forums.sandisk.com/t/wd-my-book-for-mac-backup-disk-not-available/412401/5 "2018-04-20T14:24:18Z")
I performed the steps in the link you mentioned and nothing got resolved. I still get the message that the backup disk is not available. Getting frustrated. ---
**Author:** ![MitchellCP](https://avatars.discourse-cdn.com/v4/letter/m/a3d4f5/32.png) [@MitchellCP](https://forums.sandisk.com/u/MitchellCP)\ **Post date:** [May 3, 2018, 11:07pm UTC](https://forums.sandisk.com/t/wd-my-book-for-mac-backup-disk-not-available/412401/6 "2018-05-03T23:07:29Z")
Did you look here? Not sure if it’s the same problem. > [@Backup fails on Time Machine](https://community.wd.com/t/backup-fails-on-time-machine/187675): > > I’m running MacOS 10.12 and can make an initial Time Machine backup and occasionally subsequent backups. However, within a day at most, I get an error telling me that ‘Backup Failed. Time Machine couldn’t complete the backup…’ to my 4TB WD My Book for Mac. It’s about a month old, and this issue has been a constant: I’ve reformatted the drive, tried Disk Utility and both running and uninstalling the WD tools. [image]