Zipfile deleted itself? Last week I downloaded a zipfile from a website on my mac. When it finished downloading the file automatically opened (which it normally doesn’t; I would normally have to double click it first). This was already strange but I didn’t think too much of it.

It asked me for a password, which I did not know. When I clicked “cancel” the archive utility just quit.

After that, when I looked in my downloads folder the file was no longer there. So I looked in my trash folder to be shocked to see that the file wasn’t there either. So basically, the file was behaving very strangely and had just deleted itself.

What does this mean? Is this just something archive utility can do? Or can it be that the file might have been malicious?
The zip file cannot “self delete”.
There is a setting for “Archive Utility” in most versions of Mac OS X / OSX / macOS where you can specify you’d like to delete Zip files after extraction.
See:


https://www.makeuseof.com/tag/delete-zip-files-after-extraction


Check if you have this feature turned on:

If you have this feature turned on already:
I believe this is intended to work only after a successful extraction.  It shouldn’t work if the extraction fails.
One possibility is that only some of the zipped files in the zip were password protected.  (Yes, you can create a zip file with a mix of password protected and “unprotected” files.)
If the zip had even just one non-password protected file (like README.TXT) that unzipped correctly, it may be present and Archive Utility might have deleted the zip.  This seems doubtful.
If you do not:

Perform a spotlight search or command-line search for the file name.
Scan your hard drive for errors using a Disk Utility.
Re-download the file (look for a link in your browser history, if needed and available.)