Trojan: Win32 / Casdet! Rfn OVER Zotero
My W10 laptop is infected with the "Trojan: Win32 / Casdet! Rfn" that windows defender (WD) detects when I use the Zotero in the version of the program installed on the laptop, which also syncs with the Zotero in the cloud. I have tried to solve it, definitively, using the WD, the Microsoft Safety Scanner and Malwarebytes Free and uninstalling and reinstalling the Zotero "stand alone" from my laptop, but shortly after starting the Zotero the Trojan appears again, always in a folder with the same name hanging from root paths / Zotero
You can paste the 8-character folder name from 'storage' into the Zotero search bar in All Fields & Tags mode in the library root to find the attachment item in question, delete it, and empty the trash, and then sync. The item will then be deleted from all synced computers.
Anyway, as I said, you'd want to delete the attachment here, not just the file, and empty the trash after. Otherwise the file would just be downloaded again later when you synced, which is what you're seeing in the screenshots you sent.