for me e: is the way to go (regexp), but your version was wrong.
2019-07-15 15:11:50.237 INFO UPLOAD_FILE Uploaded Chattel/Jobs Current/Beverly Hills - Eskijian, Naira - 426-428 South Roxbury Drive/Files from client/Thumbs.db (192000)
e:thumbs.db
As you can see, the file that was uploaded is Thumbs.db and not thumbs.db
If you check for example my filters file:
you can see that i am using
e:(?i)(^|/)thumbs\.db$
which looks a little bit complicated because i’m trying to not exclude “possibly useful files”. See here what i’m matching: regex101.com.
What you need at minimum for the regexp version is:
e:(?i)thumbs\.db
more specifically: (?i) which sais: make this case insensitive.
Note: I don’t think using the second regex is safe and you can also test it at the link above and see what this matches compared to the one in my filters. (imo it matches too many files which may actually be needed in the backup)