Refer to the tutorial on the Web and use disk Tools to create a “sparse Disk image” in the Shared folder, then use the command to set it to the target disk of the TimeMachine.

sudo tmutil setdestination -a /Volumes/SMBTimeMachine

But the error:

/Volumes/SMBTimeMachine: Disk does not support Time Machine backups. (error 45)
The backup destination could not be added.

For a long time, Google did not find a solution, but finally found a solution sharing method with Apple’s help, and finally solved it smoothly:
1, use the command line tool to create a “sparse binding disk image”, not “Disk Tools”, I tried using “Disk Tools” still does not work, there is no problem with the command line.

sudo hdiutil create -size 260g -type SPARSEBUNDLE -nospotlight -volname "SMBTimeMachine" -fs "Case-sensitive Journaled HFS+" -verbose /Volumes/yanghl/HaiLong_Mac_TimeMachine.sparsebundle

“SMBTimeMachine” is the label of the newly created disk image, followed by the path saved to the disk image file, “-size 260g” is the size of the disk image, these parameters can be changed.
command run output reference:

Initializing...
Creating...
DIDiskImageCreatorProbe: interface  1, score     1000, CSparseBundleDiskImage
DIDiskImageCreatorProbe: interface  2, score    -1000, CSparseDiskImage
DIDiskImageCreatorProbe: interface  3, score    -1000, CRawDiskImage
DIDiskImageCreatorProbe: interface  7, score    -1000, CWOUDIFDiskImage
DIDiskImageCreatorProbe: interface  9, score    -1000, CCFPlugInDiskImage
DIDiskImageCreateWithCFURL: CSparseBundleDiskImage
CBSDBackingStore::createProbe directory, not a valid image file.
DIBackingStoreCreatorProbe: interface  0, score    -1000, CBSDBackingStore
DIBackingStoreCreatorProbe: interface  1, score     1000, CBundleBackingStore
DIBackingStoreCreatorProbe: interface  2, score        0, CRAMBackingStore
DIBackingStoreCreatorProbe: interface  3, score      100, CCarbonBackingStore
DIBackingStoreCreatorProbe: interface  5, score     -100, CCURLBackingStore
DIBackingStoreCreateWithCFURL: CBundleBackingStore
DIFileEncodingCreatorProbe: interface  2, score    -1000, CEncryptedEncoding
DIBackingStoreCreatorProbe: interface  0, score      100, CBSDBackingStore
DIBackingStoreCreatorProbe: interface  1, score    -1000, CBundleBackingStore
DIBackingStoreCreatorProbe: interface  2, score        0, CRAMBackingStore
DIBackingStoreCreatorProbe: interface  3, score      100, CCarbonBackingStore
DIBackingStoreCreatorProbe: interface  5, score     -100, CCURLBackingStore
DIBackingStoreCreateWithCFURL: CBSDBackingStore
DIBackingStoreCreateWithCFURL: creator returned 0
DIBackingStoreCreateWithCFURL: creator returned 0
DIDiskImageCreateWithCFURL: creator returned 0
DI_kextWaitQuiet: about to call IOServiceWaitQuiet...
DI_kextWaitQuiet: IOServiceWaitQuiet took 0.000007 seconds
Formatting...
near completion...
created: /Volumes/yanghl/HaiLong_Mac_TimeMachine.sparsebundle
hdiutil: create: returning 0

2. When finished, find the disk image file in the Finder and double-click to load it. Then use the command:

sudo tmutil setdestination -a /Volumes/SMBTimeMachine/

3. The command was successfully executed without any output. Go to system Settings -& GT; “TimeMachine”, you can see that “SMBTimeMachine” has been set as the target disk.
This should allow the TimeMachine to proceed normally.
Note: It is currently found that this method must be backed up all at once. If the backup is interrupted, the SparseBundle disk image, once unmounted, can no longer be loaded because the file is incomplete and cannot be reloaded without a backup

The article published at the same time in my Jane books: https://www.jianshu.com/p/9f56587af82c