*** If SDCARD is not available, check the FAQ “4.2.SDCARD or USB media is not recognized by the app”.

*** There is a danger of losing the file, so when creating a new task you must create a test directory and test it.

***FAQs.
https://drive.google.com/file/d/1a8CTRu9xoCD74Qn0YZxzry-LHxQ8j7dE/view?usp=sharing

-Function
SMBSync 2 is a tool for synchronizing files via wireless LAN using SMB1, SMB2 or SMB3 protocol between the internal storage of Android terminal, SDCARD and PC/NAS. Synchronization is a one-way from the master to the target, mirror, move, copy, archive can be used. (Internal storage, SDCARD, SMB, ZIP combination is possible)
Can start the sync by external application (Tasker, AutoMagic etc) or SMBSync2 schedule.

・Mirror
If master and target files are different, to copied files from master to the target directory. To delete target files and directories if does not exist in the master.
・Move
If master and target files are different, to copied files from master to the target directory. To delete the master directories and files copied to the target.
However, the master and target same name, same file modification time and file size, to delete the file on the master without copying files.
・Copy
If master and target files are different, to copied files from master to the target directory. However, the same file modification time and file size with the same name does not copy the master and target.
・Archive
Move photos and videos in the directory on the master side to the target under conditions such as shooting date/time than the date and time of archive execution, such as 7 days or earlier or 30 days or earlier. (However, ZIP can not be used for target)

Note1:
The difference file is one of the following three conditions.
1. File does not exist
2. Different file sizes
3. Different over when last updated 3 seconds

Note2:
The last update time of the file sync to the internal storage may be rewritten to the sync time depending on the model. Also, the last update time of external SDCARD is always rewritten to synchronized time on Android 5/6.

For more information :
https://blog.goo.ne.jp/fhoshino/e/d5f1d3077ab101ea6957a7029f09f1cc