How to run FSCK on Catalina without Single User Mode??

[cb911]

Have not needed Single User Mode on the new MBP (15" 2019) until now when an 3TB Toshiba external HDD wouldn't mount. Was fine until I slept the Mac, then wouldn't mount and was greyed out in Disk Utility. Tried First Aid and it failed with error 69845. Tried to boot into Single User Mode holding Cmd + S during startup and it does show the white text on black screen but still boots into Mac OS? So SUM is now gone??

Recovery Mode didn't help either - tried Disk Utility there and got the same error.

What else can I try?

The external drive is formatted ExFAT - am I better off just transferring the files to a Windows computer and formatting the external HDD to HFS and putting the files back on? Or is it any help to boot the MBP into Windows (dual boot) and try something there?

Cheers for any tips.

 

[chscag]

The external drive is formatted ExFAT - am I better off just transferring the files to a Windows computer and formatting the external HDD to HFS and putting the files back on? Or is it any help to boot the MBP into Windows (dual boot) and try something there?

Those certainly would work, but how are you going to do that if the drive won't mount? I'm no longer familiar with what tools are available for Windows, but it may be better to use your Windows machine to see if you can repair the drive. Fat and exFat are non journaled file systems and can be flaky at times.

 

[posguy99]

Have not needed Single User Mode on the new MBP (15" 2019) until now when an 3TB Toshiba external HDD wouldn't mount. Was fine until I slept the Mac, then wouldn't mount and was greyed out in Disk Utility. Tried First Aid and it failed with error 69845. Tried to boot into Single User Mode holding Cmd + S during startup and it does show the white text on black screen but still boots into Mac OS? So SUM is now gone??

Is single-user mode (SUM) dead?

Single-user mode to run fsck to check and repair your boot disk became tricky with Fusion Drives. With a T2 chip, it’s not practical in its traditional form.

eclecticlight.co

 

[ght56]

ExFAT, as you likely know, is extremely prone to corruption and so I would imagine this is your issue. If so, Windows should be able to mount and repair the disk pretty easily by just connecting the drive to the OS...if not, run a Chkdsk /r/x through Cmd. macOS has never been as good at repairing damaged ExFAT volumes IMHO, so just because Mac isn't knocking this out I would not assume it was a lost cause. While you are at it in your Win10 OS, you might want to check the drive health with CrystalDiskInfo or some equivalent to make sure this isn't related to a physical failure.