Warning - Can't open file
AFAIK ".chk" files are results from from the chkdsk tool. You have to ask yourself, why is it there? Might there be something important inside it?
But your error Win32 status code of decimal 1392 is listed here:
https://docs.microsoft.com/en-us/windows/win32/debug/system-error-codes--1300-1699-
...as:
ERROR_FILE_CORRUPT
1392 (0x570)
The file or directory is corrupted and unreadable.
...so it looks like the .chk file itself is corrupt, and this is most unusual...
...it seems to me that the disk / volume that the .chk file is on is having quite a few problems...
...so, I think you need to:
1) run a chkdsk now (but not a repair) and see what the result is
...if you have continued errors then: 2a) schedule a time to run a full chkdsk repair during boot/reboot
...if there are no more errors then: 2b) try deleting the stale old .chk file and retry the backup
