Random empty files appearing in c:\
Starting a couple of weeks ago, I began noticing that occasionally (every 2-3 days usually), a few empty files appear in my c:\ folder (Windows 10, as up-to-date as Windows ever is). They have names like "wal3A7109C6" (no file extension). Usually 4-5 will be generated at the same time (ie, same timestamp, so within the same second).
When I first noticed them, I (nervously) deleted a batch with no apparent consequences - but I had to activate Administrator privileges to get rid of them. I ran virus scans but have seen nothing unusual.
A few minutes ago, I had Firefox open but minimized to the task bar. I also happened to have c:\ open in a Window I could see. As I tapped to expand the browser, another of the files appeared, and the browser window behaved oddly for a moment, as though about to crash. The last few versions - I'm at 125.0.3 (64 bit) - have been crashing more than I'm accustomed to, but this is the first time I'd considered the browser to be a likely suspect.
Does anyone have any clues/possibilities to offer? It would be much appreciated.
All Replies (2)
Getting zero-byte .htm files can be caused by downloading a file over an insecure HTTP link from a secure HTTPS page (i.e. mixed content is on the page) or by Firefox sending a HTTP background request in HTTPS-Only mode and "dom.block_download_insecure = true" in about:config.
- /questions/1375411 Firefox downloading 0 byte htm files moz-safe-about resources
You can look at these prefs in about:config:
- dom.security.https_only_mode_send_http_background_request => false
- dom.block_download_insecure
Thanks for your reply. I've seen discussions of .htm files, but I always run with visible file extensions configured in Windows so I didn't think they'd apply. On my system .htm & .html files are both associated with default apps. The files in question do not show any extension at all, and show as not having any associated app, so can they still be .htm files?
Anyway, I'm going to change out the suggestions, leaving the background_request one for last, to see if it helps and also what it has in way of consequences. I remember a few revs back that I had some file downloads that would always block on the security point, and that was a pain. I downloaded them anyway (since I knew why they were being flagged), quarantined and ran virus check on them. I was glad when that stopped happening, so perhaps the default for that config item was flipped during one of the updates?
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