Strange ... on a Linux box, the data/temp/backup/ directory on a 2.4 not having issues shows log files like:
699f1b0851f0dff3f7701e7a6fe6f52b.log
[root@sos backup]# ls -l
total 0
-rw-rw-rw- 1 apache apache 0 Dec 4 17:41 699f1b0851f0dff3f7701e7a6fe6f52b.log
And that contains 0 bytes ... ie, nothing in it ... indicating a successful backup.
If you find a log file in that location, in previous versions of Moodle, they would be text (NOT zipped) and opening one in a text editor was all that was needed to inspect. So open NotePad first, then have it look for .log files in the appropriate directory.
Let's have a look see at your DB:
select * from mdl_files where component="backup";
From the looks of what was copied and pasted, was a file with a hashname like 699f1b0851f0dff3f7701e7a6fe6f52b opened? or attempted to open it? That really might be a hash named *zip* file.
Copy that hash named file out into a temp directory. Rename it:
699f1b0851f0dff3f7701e7a6fe6f52b to 699f1b0851f0dff3f7701e7a6fe6f52b.zip
and unzip it.
It is the failed backup, BTW. Inspection of it can sometimes help find a clue as to what is NOT being backed up.
Also suggest turning on debugging and run a backup to see what it says.
'spirit of sharing', Ken
NOTE: can't believe no Windows users bother to respond! Shame on them!