I have a disk that got disabled but Unraid can read temperature from it.

SMART is also ok.

Please post the diagnostics.

Sorry... here it is

unraid-diagnostics-20230424-1233.zip

Device was already disabled at last boot, so we can't see what happened, but since SMART looks good and the emulated disk is mounting you can rebuild on top:

 

https://wiki.unraid.net/Manual/Storage_Management#Rebuilding_a_drive_onto_itself

I have started the rebuld now.
Goes very slow...

 

post new diagnostics

unraid-diagnostics-20230424-1402.zip

It stopped sync.
Got this in the log.
Seems like the disk isnt healty..or motherboard config bad ?
Disk only approx 1 month old
Apr 24 11:37:27 Unraid  emhttpd: EMTEC_X150_2000GB_F2247X150N0386 (sdc) 512 3907029168
Apr 24 11:37:27 Unraid kernel: mdcmd (3): import 2 sdc 2048 1953513560 0 EMTEC_X150_2000GB_F2247X150N0386
Apr 24 11:37:27 Unraid kernel: md: import disk2: (sdc) EMTEC_X150_2000GB_F2247X150N0386 size: 1953513560 
Apr 24 11:37:27 Unraid  emhttpd: read SMART /dev/sdc
Apr 24 13:15:32 Unraid  emhttpd: read SMART /dev/sdc
Apr 24 13:16:10 Unraid  emhttpd: EMTEC_X150_2000GB_F2247X150N0386 (sdc) 512 3907029168
Apr 24 13:16:10 Unraid  emhttpd: read SMART /dev/sdc
Apr 24 13:16:26 Unraid unassigned.devices: Disk with ID 'EMTEC_X150_2000GB_F2247X150N0386 (sdc)' is not set to auto mount.
Apr 24 13:19:08 Unraid  emhttpd: read SMART /dev/sdc
Apr 24 13:20:01 Unraid  emhttpd: EMTEC_X150_2000GB_F2247X150N0386 (sdc) 512 3907029168
Apr 24 13:20:01 Unraid kernel: mdcmd (3): import 2 sdc 2048 1953513560 0 EMTEC_X150_2000GB_F2247X150N0386
Apr 24 13:20:01 Unraid kernel: md: import disk2: (sdc) EMTEC_X150_2000GB_F2247X150N0386 size: 1953513560 
Apr 24 13:20:01 Unraid  emhttpd: read SMART /dev/sdc
Apr 24 14:49:07 Unraid kernel: ata2.00: exception Emask 0x0 SAct 0x3000 SErr 0x0 action 0x6 frozen
Apr 24 14:49:07 Unraid kernel: ata2.00: failed command: WRITE FPDMA QUEUED
Apr 24 14:49:07 Unraid kernel: ata2.00: cmd 61/10:60:a0:be:35/03:00:0f:00:00/40 tag 12 ncq dma 401408 out
Apr 24 14:49:07 Unraid kernel: ata2.00: status: { DRDY }
Apr 24 14:49:07 Unraid kernel: ata2.00: failed command: WRITE FPDMA QUEUED
Apr 24 14:49:07 Unraid kernel: ata2.00: cmd 61/f8:68:b0:c1:35/03:00:0f:00:00/40 tag 13 ncq dma 520192 out
Apr 24 14:49:07 Unraid kernel: ata2.00: status: { DRDY }
Apr 24 14:49:07 Unraid kernel: ata2: hard resetting link
Apr 24 14:49:10 Unraid kernel: ata2: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
Apr 24 14:49:10 Unraid kernel: ata2.00: configured for UDMA/133
Apr 24 14:49:10 Unraid kernel: ata2: EH complete
Apr 24 14:55:46 Unraid kernel: ata2.00: exception Emask 0x0 SAct 0x180 SErr 0x0 action 0x6 frozen
Apr 24 14:55:46 Unraid kernel: ata2.00: failed command: WRITE FPDMA QUEUED
Apr 24 14:55:46 Unraid kernel: ata2.00: cmd 61/40:38:e0:e3:0d/05:00:10:00:00/40 tag 7 ncq dma 688128 out
Apr 24 14:55:46 Unraid kernel: ata2.00: status: { DRDY }
Apr 24 14:55:46 Unraid kernel: ata2.00: failed command: WRITE FPDMA QUEUED
Apr 24 14:55:46 Unraid kernel: ata2.00: cmd 61/10:40:20:e9:0d/03:00:10:00:00/40 tag 8 ncq dma 401408 out
Apr 24 14:55:46 Unraid kernel: ata2.00: status: { DRDY }
Apr 24 14:55:46 Unraid kernel: ata2: hard resetting link
Apr 24 14:55:49 Unraid kernel: ata2: SATA link up 6.0 Gbps (SStatus 133 SControl 300)
Apr 24 14:55:49 Unraid kernel: ata2.00: configured for UDMA/133
Apr 24 14:55:49 Unraid kernel: sd 2:0:0:0: [sdc] tag#6 UNKNOWN(0x2003) Result: hostbyte=0x03 driverbyte=DRIVER_OK cmd_age=38s
Apr 24 14:55:49 Unraid kernel: sd 2:0:0:0: [sdc] tag#6 CDB: opcode=0x2a 2a 00 10 0d df e8 00 03 f8 00
Apr 24 14:55:49 Unraid kernel: I/O error, dev sdc, sector 269344744 op 0x1:(WRITE) flags 0x0 phys_seg 127 prio class

Try replacing cables and/or swapping SATA port, if issues persist it's likely a device problem.